Peppermint Soothe by Nature's Way

LIKELY EFFECTIVE

• Irritable bowel syndrome (IBS). Oral enteric-coated peppermint oil is conditionally recommended by the American College of Gastroenterology (ACG) for the relief of global IBS symptoms, such as abdominal pain. Details: The ACG conditionally recommends the use of peppermint for the relief of global IBS symptoms. This recommendation is based on an available meta-analysis of generally low-quality clinical research (105124). Several clinical trials and meta-analyses show that taking enteric-coated peppermint oil 1-2 capsules orally two to four times daily reduces abdominal pain, distention, flatulence, and bowel movements in patients with IBS. Each capsule provides approximately 0.2 mL of peppermint oil or 180-225 mg peppermint oil. Most trials have used specific products (Colpermin, Tillotts Pharma; Mintoil, Cadigroup; Ibgard, IM HealthScience, Tempocol) (3802,3803,4469,11778,11779,17681,17682,68467,68515,68522)(68603,68604,68605,96360,99493,109980). The most recent meta-analysis to date shows that four patients would need to take peppermint oil to prevent one patient from having persistent IBS symptoms, and seven patients would need to take peppermint oil to prevent one patient from having abdominal pain. However, the individual studies included in the analysis lasted no more than 12 weeks (109980); any long-term effects are unclear. Although most studies have shown benefit for reducing symptoms, some older studies have found no significant effect (11777,11789) or only short-term benefits (68620). Also, a well-designed study shows that taking peppermint oil capsules designed for either small intestinal release (enteric-coated) or ileocolonic release does not increase the number of people with at least a 30% decrease in abdominal pain over a period of 4 weeks, although symptoms are modestly reduced when compared with placebo (102602). Another clinical trial in patients with moderate to severe IBS shows that taking a specific enteric-coated formulation of peppermint oil (Pepogest; Nature's Way) 180 mg three times daily for 6 weeks does not further improve symptom severity when compared with placebo. However, both groups experienced a large improvement on the IBS-Severity Scoring System (IBS-SSS) and the IBS Global Improvement Scale (107955). The validity of these findings is limited due to lost data and inconsistent follow-up; additionally, adverse effects occurred more frequently in the peppermint oil group. The reasons for these negative findings are unclear but may include short treatment durations and the use of different formulations; additionally, IBS is comprised of various subtypes and symptoms that can range in severity and presentation, which may alter treatment response. Some clinical research has also evaluated a specific combination product (Atrantil, KBS Research) containing peppermint leaf, red quebracho extract, and conker tree extract. Taking this product as needed for 2 weeks seems to reduce constipation and bloating when compared to baseline in patients with constipation-predominant IBS (95429,95430). It is unclear if the effects of this product are due to peppermint, the other ingredients, or the combination.

POSSIBLY EFFECTIVE

• Barium enema-related colonic spasm. Rectal peppermint, as part of barium enema preparations, seems to reduce colonic spasms during examination. Oral peppermint also seems to be beneficial. Details: Rectal use of peppermint oil, added as an ingredient in barium enema preparations, seems to relax the colon during barium enema examination and reduce the percentage of patients who experience colonic spasms by about 25% to 30% (6739,6749,12009). Adding peppermint oil to the barium enema seems to be at least as effective as using systemic scopolamine (Buscopan). Adding peppermint oil to the barium solution also does not seem to impair image quality (12009). Some clinical research also shows that taking peppermint oil orally before the start of a double-contrast barium enema examination decreases spasms and might also increase diagnostic quality (14467).
• Chemotherapy-induced nausea and vomiting (CINV). Oral and inhaled peppermint seem to reduce nausea and vomiting in patients with CINV. Details: Clinical research shows that adding peppermint oil, 40 drops in 20 mL water, every 8 hours following chemotherapy treatment to treatment with standard antiemetics reduces the severity of nausea, vomiting, and anorexia by moderate to large amounts over 48 hours when compared with a plain water placebo (105123). The use of peppermint oil aromatherapy has also been investigated. Clinical research shows that adding 2 drops of peppermint oil to a cool, damp washcloth for use on the neck as aromatherapy for about 30 minutes helps relieve chemotherapy-induced nausea by a small amount when compared with a washcloth without peppermint oil (102603). Additional clinical research in patients receiving standard antiemetics after chemotherapy shows that applying one drop of peppermint oil below the nose three times daily for 5 days reduces the severity of nausea and the frequency of nausea, vomiting, and retching by a moderate to large amount when compared with the antiemetics alone. These parameters were not improved following treatment with cisplatin (105122). In children with acute leukemia, a small clinical study shows that aromatherapy with 2 drops of peppermint oil and 3 drops of lemon oil in 80 mL of water diffused 30 minutes prior to and 2 and 4 hours after chemotherapy once weekly for 4 weeks decreases the severity of nausea, vomiting, and retching, and improves quality of life scores when compared with diffused water or no intervention (112015). The validity of these findings is limited by the use of patient-reported outcomes.
• Dyspepsia. Oral peppermint, in combination with caraway and possibly other ingredients, seems to reduce symptoms of dyspepsia. It is unclear if oral peppermint alone is beneficial. Details: Some clinical research shows that taking specific products containing peppermint and caraway oil (Enteroplant, Dr Willmar Schwabe Pharmaceuticals; Menthacarin, Dr Willmar Schwabe GmbH & Co.) improves quality of life and reduces symptoms of dyspepsia, including feelings of fullness, pain, and mild gastrointestinal spasms (6740,6741,10075,96344,102600). A meta-analysis of three of these clinical studies shows that taking this combination product 2-3 times daily for 4 weeks modestly reduces abdominal pain when compared with placebo (110091). Taking this combination twice daily for 4 weeks also improves postprandial distress syndrome and epigastric pain syndrome, two subtypes of dyspepsia, when compared with placebo (96344). The combination of enteric-coated peppermint oil 90 mg and caraway oil 50 mg appears to be comparable to cisapride for relieving dyspepsia when taken 2-3 times daily for up to 4 weeks (6740,6741,10075). However, most trials investigating this combination are small and/or of overall low quality (102600). A specific combination product containing peppermint leaf (Iberogast, Steigerwald Arzneimittelwerk GmbH) also seems to improve symptoms of dyspepsia. The combination includes peppermint leaf plus clown's mustard plant, German chamomile, caraway, licorice, milk thistle, angelica, celandine, and lemon balm (7049). A meta-analysis of studies using this combination product shows that taking 1 mL orally three times daily over a period of 4 weeks reduces the severity of acid reflux, epigastric pain, cramping, nausea, and vomiting when compared with placebo (13089). A similar combination product containing extracts from peppermint leaf, clown's mustard plant, German chamomile flower, caraway, licorice root, and lemon balm (STW 5-II, Steigerwald Arzneimittelwerk GmbH) 1 mL taken three times daily for up to 8 weeks eliminates gastrointestinal symptoms in 40% more dyspepsia patients when compared with placebo (12724).
• Endoscopy-associated adverse effects. Intraluminal peppermint seems to reduce spasticity during an endoscopy. It is unclear if oral peppermint is beneficial for reducing adverse effects related to endoscopy. Details: A meta-analysis of four clinical trials show that peppermint oil, administered orally or intraluminally, reduces the incidence of spasticity by about 41% when compared with placebo in patients undergoing endoscopy, with severe spasticity occurring at about 30% the rate of those taking placebo. However, there was no effect on subjective pain (102604). Individual clinical studies show that intraluminal peppermint oil can reduce both pain and spams in patients undergoing endoscopy (18220,68371,68395,68445,68532). However, there are limitations with this form of administration, including cost and practicality, which has led to interest in the use of oral formulations (104221). Studies evaluating oral extended-release peppermint have been conflicting. While one study shows that a specific extended-release peppermint oil product (Colpermin) 187 mg or 0.2 mL taken orally 4 hours prior to a colonoscopy reduces procedure time, pain, and spasticity (68532), a study using another specific extended-release peppermint oil (IBGard) did not show an effect on colonic spasms, procedure time, or adenoma detection rate when compared with placebo (104221). These differing outcomes may be due to timing of administration. The study that showed benefit administered the treatment 4 hours prior to endoscopy, whereas the study showing no benefit administered the treatment only 1 hour prior. This suggests that extended-release peppermint may need to be administered at least 4 hours prior to the procedure to allow for adequate colonic release (68532,102604,104221).
• Nipple fissures. Topical peppermint seems to reduce cracked skin and pain in the nipples due to breastfeeding. Details: Clinical research shows that topical application of peppermint oil in gel or water reduces cracked skin and pain in the nipple area from breastfeeding when compared with using placebo, lanolin, or the expressed breast milk technique (68454,68462). Other research shows that applying peppermint oil in cream immediately after breastfeeding for 2 weeks decreases pain and trauma in the nipple area similarly to the topical application of dexpanthenol or lanolin (96365).
• Pressure ulcers. Topical peppermint seems to reduce the risk of pressure ulcers. Details: Clinical research in bedridden patients shows that prophylactic application of a topical gel containing peppermint oil 0.2% three times daily for up to 14 days results in pressure injuries in about 23% of patients compared with 77% of those given a placebo gel (102605).
• Tension headache. Topical peppermint seems to relieve tension headaches. Details: Clinical research shows that topical application of peppermint oil 10% relieves tension headaches when compared with placebo (3801,6190).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Abdominal pain. Although there has been interest in using oral peppermint for abdominal pain, there is insufficient reliable information about the clinical effects of peppermint for this condition.
• Anxiety. It is unclear if inhaled peppermint oil is beneficial for reducing anxiety. Details: A clinical trial in patients presenting to the emergency department for an acute coronary syndrome event shows that placing 3 drops of peppermint oil on a cotton ball and inhaling for 1 hour improves anxiety and respiratory rate when compared with baseline or placebo (107958). Due to the single-dose nature of this study, the effects of repeated inhalation of peppermint oil are unclear.
• Athletic performance. It is unclear if oral peppermint oil is beneficial for athletic performance. Details: Preliminary clinical research in trained adult runners shows that taking peppermint essential oil, 0.05 mL diluted in 500 mL of water, orally once 30 minutes before exercise improves running time to exhaustion by 11% when compared with placebo (112742).
• Breast cancer-related hot flashes. It is unclear if topical peppermint is beneficial for reducing hot flashes in patients with breast cancer. Details: Preliminary clinical research shows that using a spray containing a combination of peppermint and neroli hydrolat does not alleviate hot flashes in most patients receiving chemotherapy for breast cancer when compared with using a plain water spray (68481).
• Cognitive function. It is unclear if inhaled peppermint oil is beneficial for improving cognitive function. Details: Preliminary clinical research shows that inhalation of peppermint oil slightly improves memory and the performance of cognitive tasks such as typing, alphabetization, and ordering, but not attention and speed of task completion, when compared with control (56954,68416,68466).
• Common cold. Although there has been interest in using oral, topical, or inhaled peppermint for the common cold, there is insufficient reliable information about the clinical effects of peppermint for this condition.
• Dental plaque. Topical peppermint has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that rinsing the mouth for one minute with 10 mL of a specific combination product (HiOra, Himalaya Herbal Healthcare) containing peppermint oil and numerous other ingredients twice daily for two days reduces plaque index or plaque area when compared with placebo; however, it was not as effective as chlorhexidine 0.2% solution (68530). It is unclear if these effects are due to peppermint oil, other ingredients, or the combination.
• Diffuse esophageal spasm. It is unclear if oral peppermint oil is beneficial for diffuse esophageal spasm. Details: A small exploratory study in adults with diffuse esophageal spasm shows that drinking a solution of peppermint oil, 5 drops in 10 mL of water, can resolve esophageal contractions when compared with baseline (13415). The validity of this finding is limited by the lack of a comparator group.
• Dysmenorrhea. It is unclear if oral peppermint oil is beneficial for reducing menstrual pain. Details: Preliminary clinical research shows that taking three capsules of peppermint oil (Colpermin; Tillotts Company or Razak company) daily for 3 days, starting on the first day of menstruation, is as effective as mefenamic acid 250 mg three times daily for reducing pain, and more effective for reducing nausea and vomiting, associated with dysmenorrhea. However, mefenamic acid was more effective for reducing bleeding and analgesic use (105125).
• Fatigue. It is unclear if inhaled peppermint oil improves fatigue in patients with cardiac disease. Details: A clinical trial in hospitalized patients with various forms of cardiac disease shows that placing 3 drops of peppermint oil on a cotton ball and inhaling for 20 minutes nightly for 7 days improves fatigue scores when compared with placebo. These improvements were similar to those seen with lavender oil inhalation. Fatigue scores decreased by 24 and 21 points in the peppermint and lavender groups, respectively, compared with a 2-point reduction in the placebo group (107959). The validity of these findings is limited due to the short duration of treatment.
• Halitosis. Peppermint has only been evaluated in combination with other ingredients as a mouthwash; its effect when used alone is unclear. Details: Preliminary clinical research shows that rinsing the mouth with a specific combination of tea tree oil, peppermint, and lemon essential oil once for three minutes improves breath smell when compared with placebo or benzydamine hydrochloride (19177). Other preliminary clinical research in elderly adults with dementia who require oral care assistance shows that cleaning the mouth with a mixture of peppermint oil, tea tree oil, and lemon essential oils diluted to 0.5%, applied via gauze, twice daily for 7 days improves halitosis scores and oral condition scores when compared with placebo (112957).
• Insomnia. It is unclear if inhaled peppermint oil is beneficial for insomnia. Details: Preliminary clinical research in cancer patients shows that receiving aromatherapy as three drops of peppermint oil applied to a cotton ball and attached to the collar for 20 minutes at bedtime for one week improves sleep when compared with baseline. However, it seems to be no better than using lavender oil aromatherapy or using a control of lavender oil 1% (103063).
• Menopausal symptoms. It is unclear if inhaled peppermint oil is beneficial for menopausal symptoms. Details: Preliminary clinical research in adults with menopausal symptoms shows that receiving aromatherapy as 2 drops of peppermint oil with upper extremity massage and for 30 minutes twice weekly for 4 weeks moderately improves menopause symptom scores, including both somatic symptoms and urogenital symptoms, when compared with placebo (112745).
• Migraine headache. It is unclear if intranasal or inhaled peppermint oil is beneficial for migraine headache. Details: Preliminary clinical research shows that using 1-2 doses of intranasal peppermint oil 1.5% (Poursina Company) at the start of migraine pain is as effective as intranasal lidocaine 4%, and more effective than placebo, for reducing migraine headache intensity. Approximately 42% of those using peppermint oil indicated a high level of headache reduction, compared with 42% of those using lidocaine and 5% of those using placebo. Also, pain relief was felt within 5 minutes in more patients using peppermint than placebo (105126). However, it is unclear if participants were truly blinded to the use of peppermint oil. Other preliminary clinical research in pediatric patients with migraine or other chronic headaches shows that receiving aromatherapy with peppermint oil over 10 minutes during a footbath does not improve pain or anxiety scores when compared with control (112746).
• Mosquito repellent. Although there has been interest in using topical peppermint oil as a mosquito repellent, there is insufficient reliable information about the clinical effects of peppermint for this purpose.
• Myalgia. Although there has been interest in using topical peppermint oil for myalgia, there is insufficient reliable information about the clinical effects of peppermint for this condition.
• Oral mucositis. Topical peppermint has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in adults undergoing stem cell transplantation shows that using an oral rinse containing peppermint oil and German chamomile three times daily, in addition to standard treatment with sodium chloride and chlorhexidine, reduces the duration and severity of mucositis and the use of narcotic analgesics when compared with placebo and standard treatment. However, this oral rinse does not reduce or delay the occurrence of mucositis or affect the duration of hospitalization (96363). Another small clinical study in adults with head and neck cancers undergoing radiation shows that rinsing with 5 mL of a polyherbal mouthwash containing peppermint oil, German chamomile, aloe vera, and honey for 1 minute 3 times daily for 6 weeks reduces oral mucositis incidence, severity, and pain when compared with chlorhexidine 0.2% and placebo (111291). Clinical research in adults receiving treatment with 5-fluorouracil shows that using an oral rinse containing peppermint, sage tea, and thyme in addition to basic oral care, starting on the first day of chemotherapy and continuing for 14 days, delays the onset of mucositis, but not the rate or severity of mucositis, when compared with basic oral care alone (96364). It is unclear if these effects are due to peppermint oil, other ingredients, or the combinations.
• Osteoarthritis. Although there has been interest in using topical peppermint oil for osteoarthritis, there is insufficient reliable information about the clinical effects of peppermint for this condition.
• Pain (acute). It is unclear if inhaled peppermint oil is beneficial for acute pain. Details: Preliminary clinical research in cardiac patients shows that peppermint oil aromatherapy reduces pain associated with intravenous catheterization by a small amount when compared with a distilled water control (102601).
• Postherpetic neuralgia. Although there has been interest in using topical peppermint oil for postherpetic neuralgia, there is insufficient reliable information about the clinical effects of peppermint for this condition.
• Postoperative ileus. It is unclear if oral peppermint oil is beneficial for the prevention of postoperative ileus. Details: Clinical research shows that taking a specific peppermint oil product (Colpermin, Tillotts Pharma) as two capsules three times daily for 5 days after routine gynecological surgery does not prevent postoperative abdominal distension and dyspepsia when compared with placebo (68602). Conversely, a small clinical study in patients undergoing elective cesarean section shows that taking 20 drops of peppermint oil 4 hours after surgery and then hourly for a total of three doses reduces the time to first bowel sounds by around 3.3 hours, first flatulence by 4.4 hours, and first stool by 5 hours when compared with placebo (110092).
• Postoperative nausea and vomiting (PONV). Some preliminary clinical studies suggest that inhaled peppermint may be beneficial for PONV. However, it is unclear if the benefit is due to aromatherapy or improved breathing patterns. Details: Some preliminary clinical research shows that using peppermint aromatherapy helps relieve postoperative nausea (3804,13415,68524,104219,104220). Inhaling peppermint oil 10% and 30% as aromatherapy reduces the severity of nausea when compared with placebo, with no significant difference between concentrations (104220). Small clinical trials show improvement in PONV within the first 4 hours after surgery. However, this effect diminishes beyond 4 hours (104219). Other preliminary clinical research shows that peppermint oil aromatherapy is no more effective for reducing postoperative nausea than inhaling isopropyl alcohol or saline (13416,68529). It is possible that any relief of postoperative nausea observed with peppermint aromatherapy results from improved breathing patterns after surgery rather than peppermint oil itself (13416,90512). One small study shows that inhaling peppermint oil while practicing controlled breathing does not appear to relieve PONV better than practicing controlled breathing alone (90512). Some preliminary clinical research shows that inhaling vapors from a mixture of peppermint, ginger, spearmint, and cardamom essential oils reduces symptoms of postoperative nausea in approximately 15% more patients when compared with inhaling ginger essential oils alone, and in approximately 43% more patients when compared with inhaling saline (89888). However, it is not clear if the effect is due to peppermint, the other oils, or the combination.
• Postoperative pain. It is unclear if inhaled peppermint oil is beneficial for postoperative pain. Details: Preliminary clinical research in adults undergoing open heart cardiac surgery shows that receiving aromatherapy with peppermint oil 10%, 0.1 mL, three times daily for 7 doses moderately improves pain scores when compared with placebo (112747). Other preliminary clinical research in adults undergoing lumbar discectomy surgery shows that receiving aromatherapy with peppermint oil 5 drops once postoperatively modestly improves pain scores and anxiety scores when compared with no intervention (112744).
• Postoperative sleep disturbance. It is unclear if inhaled peppermint oil is beneficial for postoperative sleep disturbance. Details: Preliminary clinical research in adults undergoing open heart cardiac surgery shows that receiving aromatherapy with peppermint oil 10%, 0.1 mL, three times daily for 7 doses modestly improves sleep scores when compared with placebo (112747).
• Pre-procedural anxiety. It is unclear if inhaled peppermint oil is beneficial for reducing anxiety prior to a medical procedure. Details: Preliminary clinical research in cardiac patients shows that peppermint oil aromatherapy does not reduce anxiety associated with intravenous catheterization when compared with a distilled water control (102601).
• Pregnancy-induced nausea and vomiting. Inhaled peppermint oil has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that aromatherapy with a mixture of 5% lemon and 5% peppermint essential oils modestly reduces the intensity of nausea and vomiting on days 2-4, but not day 1, when compared with placebo aromatherapy. When nauseated, patients placed three drops of the essential oil mixture (Barij Essence Co.) onto a cotton ball held 3 cm from the nose. This action could be repeated after 5 minutes if needed (105121).
• Pruritus. Some preliminary clinical studies suggest that topical peppermint oil improves itching of various etiologies. Details: Preliminary clinical research in adults with renal, hepatic, or diabetic pruritus shows that topical application of peppermint oil 5% in petrolatum twice daily for 2 weeks improves symptoms of pruritus when compared with petrolatum alone (96361). Preliminary clinical research in patients with severe or intractable pruritus secondary to burn scars shows that applying a specific product (Chongqing No.1, CQ-01, MJ Medical Gel Systems Ltd.) containing peppermint oil 3.6%, menthol 1.4%, and methyl salicylate 2.5%, covered with gauze for 24 hours, reduces the severity of pruritus for up to 7 days after application when compared with hydrogel covered with gauze or with gauze alone (96362). Preliminary clinical research in females experiencing itchy skin due to intrahepatic cholestasis of pregnancy also shows that applying peppermint oil 0.5% in sesame oil twice daily for 2 weeks reduces pruritus severity approximately 1.8-fold when compared with sesame oil alone (89478).
• Small intestinal bacterial overgrowth (SIBO). Although there has been interest in using oral peppermint for SIBO, there is insufficient reliable information about the clinical effects of peppermint for this condition.
• Stress. It is unclear if inhaled peppermint oil is beneficial for stress. Details: Clinical research shows that peppermint aromatherapy decreases physical and perceived levels of stress when compared with baseline (68422,68517). A small clinical study in adults undergoing a virtual reality (VR) driving scenario to test road rage shows that exposure to peppermint oil (Pure Essential Oil of Peppermint, Tisserand Aromatherapy) 5 drops via fan diffuser improves aggressive driving behavior scores but does not seem to improve self-reported stress, aggression, alertness, happiness, or calmness when compared with controls that did not receive aromatherapy during the VR session (112017).
• Toothache. Although there has been interest in using topical peppermint oil for toothache, there is insufficient reliable information about the clinical effects of peppermint for this condition.
• Urticaria. Although there has been interest in using topical peppermint oil for urticaria, there is insufficient reliable information about the clinical effects of peppermint for this condition. More evidence is needed to rate peppermint for these uses.

(Read more about PEPPERMINT)

POSSIBLY EFFECTIVE

• Memory. Oral rosemary seems to improve memory in young adults. It is unclear if rosemary aromatherapy improves memory. Details: Clinical research in healthy adults shows that taking rosemary 500 mg orally twice daily for one month improves memory by approximately 14% when compared with placebo (98536). Other preliminary clinical research shows that applying four drops of pure rosemary essential oil (Tisserand Aromatherapy) to an aromatherapy diffuser pad 5 minutes before a single test period can improve the quality, but not the speed, of memory recall, and increase alertness and contentment more than lavender aromatherapy or no aroma (18323). Rosemary aromatherapy has also been evaluated for improving memory in adults with kidney failure. A small clinical study in patients (mean age 53 years) undergoing hemodialysis shows that aromatherapy with rosemary essential oil three times weekly for 1 month does not improve medication adherence or measures of prospective and retrospective memory when compared with a control group. In this study, five drops of rosemary essential oil were applied to gauze, which was then placed 10 cm from the patient's nose for 30 minutes starting 1 hour after hemodialysis (109559).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Abortion. Although there has been interest in the use of oral rosemary as an abortifacient, there is insufficient reliable information about the clinical effects of rosemary for this purpose.
• Age-related cognitive decline. It is unclear if oral rosemary is beneficial for age-related cognitive decline. Details: A small clinical study in healthy individuals aged 65-90 years shows that a single 750 mg dose of powdered rosemary leaf in tomato juice may improve memory speed. However, higher single doses of 1500-6000 mg seem to have a deleterious effect on memory speed. For other measures of attention and memory, there were no clear benefits across the range of doses from 750-6000 mg (18246). Oral rosemary has also been evaluated in combination with other ingredients. A small clinical study in healthy adults aged 62 years or younger shows that taking a combination product containing equal parts rosemary, lemon balm, and sage twice daily for 2 weeks modestly improves word recall when compared with placebo. However, it does not appear to have benefit in adults aged 63 years and older (97277). It is unclear if any benefit is due to rosemary, other ingredients, or the combination.
• Alopecia areata. Topical rosemary oil has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that rosemary oil 114 mg, in combination with lavender oil 108 mg, thyme oil 88 mg, and cedarwood oil 94 mg, mixed with jojoba oil 3 mL and grapeseed oil 20 mL and applied topically to the scalp, improves hair growth in 44% of patients, compared with 15% of those receiving placebo. This combination was massaged into the scalp for a minimum of 2 minutes, followed by wrapping the head in a warm towel, every night for 7 months (5177).
• Androgenic alopecia. It is unclear if topical rosemary is beneficial for androgenic alopecia. Details: Preliminary clinical research shows that applying rosemary oil (Barij Essence Pharmaceutical Company) 1 mL to the scalp twice daily for 6 months is as effective as minoxidil 2% for increasing hair count in patients with androgenic alopecia (91729).
• Depression. It is unclear if oral rosemary is beneficial for major depressive disorder. Details: A small clinical trial among adults newly diagnosed with major depressive disorder and recent initiation of antidepressant medication shows that taking rosemary dried leaf extract 650 mg twice daily for 8 weeks might reduce some symptoms of depression and anxiety when compared with placebo (112141). However, the validity of these findings is limited by differences in baseline depression symptom scores between groups.
• Diabetes. It is unclear if oral rosemary is beneficial for improving glycemic control in patients with type 2 diabetes. Details: In patients with type 2 diabetes, preliminary clinical research shows that taking rosemary tea daily for 90 days decreases glycated hemoglobin levels by 15% and waist and hip circumference by 6% and improves insulin resistance. However, there was no effect on fasting blood glucose, lipid profile, body weight, or body mass index (BMI). The tea was made by adding rosemary 2 grams to a liter of boiling water for 3 minutes and then passing through a sieve (105323). Other preliminary clinical research in adults with type 2 diabetes shows that taking rosemary powder 3 grams daily for 4 weeks does not reduce fasting blood glucose levels or improve lipid profile when compared with baseline. These endpoints were improved in a group of healthy adults (105327). The validity of the findings from these studies is limited by the lack a comparator group.
• Diabetic nephropathy. Oral rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a specific combination product (Canephron N, Bionorica) containing 18 mg each of rosemary leaf, centaury herb, and lovage root per tablet, as two tablets three times daily for 6 months along with standard antidiabetes treatment and enalapril (Vasotec), decreases microalbuminuria by 73%, decreases albumin:creatinine ratio by 46%, increases high-density lipoprotein (HDL) cholesterol by 25%, and lowers triglyceride levels by 43%, but does not improve glomerular filtration rate, when compared to baseline. Improvements were greater in those taking the combination product than in those treated only with standard antidiabetes therapy and enalapril. However, the combination product does not appear to improve reductions in total cholesterol or low-density lipoprotein (LDL) cholesterol (91726).
• Dysmenorrhea. It is unclear if oral rosemary is beneficial for dysmenorrhea. Details: In patients with moderate primary dysmenorrhea, clinical research shows that taking rosemary extract 220 mg every 8 hours for the first three days of the menstrual cycle, repeated for two menstrual cycles, is as effective as mefenamic acid for reducing average pain and bleeding when compared with two baseline cycles (105328).
• Fatigue. Oral rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in healthy young adults with below-average energy levels shows that taking a single dose of a mixture of rosemary from Albania (Rosmarinus officinalis) and Morocco (Rosmarinus eriocalyx) 1.7 grams does not consistently improve sustained attention, motivation to perform cognitive tasks, mental energy, or mental fatigue when compared with placebo (91731).
• Fibromyalgia. Oral rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in patients with fibromyalgia shows that taking an oral product containing rosemary leaf extract, oleanolic acid from olive leaf, and rho iso-alpha acids from hops (Meta050, Metagenics), at a dose of 440 mg three times daily for 4 weeks, then 880 mg twice daily for 4 weeks, does not improve symptoms when compared to baseline (18327).
• Gingivitis. A mouth rinse containing rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with mild to moderate gingivitis and mild plaque shows that rinsing the mouth with 10 mL of mouthwash containing 5% v/v of a combined alcoholic extract of rosemary, calendula, and ginger for 30 seconds twice daily after meals for 2 weeks decreases plaque formation, gingival inflammation, and gingival bleeding similarly to chlorhexidine gluconate 0.2% mouthwash and better than a placebo mouthwash (93555).
• Hypertension. Although there is interest in using oral rosemary for hypertension, there is insufficient reliable information about the clinical effects of rosemary for this condition.
• Hypotension. It is unclear if oral rosemary is beneficial for hypotension. Details: Preliminary clinical research in patients with primary hypotension shows that taking rosemary essential oil (Metapharmaceutical) 1 mL every 8 hours for 44 weeks increases systolic blood pressure by 13 mmHg and diastolic blood pressure by 7 mmHg when compared to baseline. However, blood pressure returned to near baseline values after treatment discontinuation (91730).
• Mental alertness. It is unclear if rosemary aromatherapy is beneficial for improving mental alertness. Details: Preliminary clinical research in nurses working on a night shift shows that placing one drop of rosemary oil on a surgical mask that is worn for 2 hours with a 10-minute on/15-minute off cycle modestly increases alertness and reduces sleepiness when compared with a water drop control (105324).
• Nonalcoholic fatty liver disease (NAFLD). It is unclear if oral rosemary leaf is beneficial in patients with NAFLD. Details: A small clinical study in patients with NAFLD shows that taking rosemary leaf powder 2 grams twice daily for 8 weeks, in conjunction with diet and exercise recommendations, does not improve measures of liver function, glycemic control, cholesterol, or body weight when compared with placebo (109561).
• Opioid withdrawal. It is unclear if oral rosemary is beneficial for opioid withdrawal when used in combination with methadone. Details: Preliminary clinical research shows that taking rosemary leaf along with methadone for 2 weeks improves symptoms of opioid withdrawal and the ability to sleep when compared with methadone alone after 3 and 7 days of treatment, but not after 2 weeks. Rosemary leaf was provided in capsules containing 300 mg each (Barij Essence Pharmaceutical Company) at a dose of 16 capsules daily for the first 3 days, 12 capsules daily for the next 4 days, and eight capsules daily for the next 7 days, in divided doses (91727).
• Osteoarthritis. Oral rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows subjective reductions in pain associated with osteoarthritis when oral formulations containing rosemary leaf extract, oleanolic acid from olive leaf, and rho iso-alpha acids from hops (NG440-2, Metagenics; Meta050, Metagenics) are used (18326,18327). The formulation used in one of these studies (Meta050, Metagenics) was taken in a dose of 440 mg three times daily for 4 weeks, then 880 mg twice daily for 4 weeks (18327). The formulation used in the other study, which was taken daily for 4 weeks, contained rosemary leaf extract 112.5 mg, oleanolic acid from olive leaf 1 mg, and rho iso-alpha acids from hops 225 mg per tablet (18326).
• Raynaud syndrome. It is unclear if topical rosemary essential oil is beneficial in patients with Raynaud syndrome. Details: A very small, open-label study in patients with Raynaud syndrome caused by systemic scleroderma shows that applying 10 drops of rosemary 10% essential oil to the hands does not increase skin temperature or improve warmth perception when compared with olive oil (109560). However, this study may have been inadequately powered to detect a difference between groups.
• Rheumatoid arthritis (RA). Oral rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows subjective decreases in pain associated with RA when oral formulations containing rosemary leaf extract, oleanolic acid from olive leaf, and rho iso-alpha acids from hops (NG440-2, Metagenics; Meta050, Metagenics) are used (18326,18327). The formulation used in one of these studies (Meta050, Metagenics) was taken in a dose of 440 mg three times daily for 4 weeks, then 880 mg twice daily for 4 weeks (18327). The formulation used in the other study, which was taken daily for 4 weeks, contained rosemary leaf extract 112.5 mg, oleanolic acid from olive leaf 1 mg, and rho iso-alpha acids from hops 225 mg per tablet (18326).
• Stress. It is unclear if rosemary aromatherapy is beneficial for stress. Details: Preliminary clinical research on the use of rosemary aromatherapy for anxiety and stress is conflicting. In a group of graduate nursing students, perceived stress associated with taking a test was lower when inhalers containing rosemary or lavender oil were used. Three drops of rosemary essential oil were added to an inhaler and inhaled before and during the test. Pulse rates, but not blood pressure, were also reduced (18324). In contrast, a small clinical study in adults aged 18-30 years shows that the aroma from diluted rosemary essential oil applied to the wrist during timed crossword puzzle completion actually increases subjective feelings of anxiety and tension when compared with placebo (18325).
• Sunburn. Oral rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a combination of rosemary and grapefruit extracts in a 1:1 ratio (NutroxSun, Monteloeder, Inc.), 250 mg orally once daily for 12 weeks, increases the amount of UV radiation needed to cause sunburn by 34% after 8 weeks and 56% after 12 weeks when compared to baseline (91728). The validity of these findings is limited by the lack of a comparator group.
• Upper respiratory tract infection (URTI). Oral rosemary has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical trial among healthy adults shows that taking a combination product containing rosemary leaf extract, aloe gel powder, and poria mushroom extract daily for 8 weeks does not reduce the frequency, duration, or severity of URTI-related symptoms when compared with placebo. However, in patients receiving an influenza vaccine midway through the study, this product does seem to improve some immune response biomarkers when compared with placebo (111921). The amount of rosemary leaf extract in the supplement was not disclosed.
• Wound healing. It is unclear if topical rosemary cream is beneficial for wound healing. Details: A moderate-sized clinical trial among primiparous adults with medio-lateral episiotomy shows that applying a cream containing rosemary extract to the wound twice daily for 10 days improves episiotomy wound healing and reduces redness and discharge when compared with placebo cream (112143). More evidence is needed to rate rosemary for these uses.

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INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging skin. It is unclear if a topical thyme flower and leaf extract reduces wrinkles. Details: A small clinical trial in healthy females aged 40-60 years with wrinkles shows that applying a specific gel preparation (ThymLec 2%, PhytoPharmaTech) containing thyme flower and leaf 1-3% extract in lecithin on the face twice daily for 60 days reduces facial wrinkles when compared with inactive control gel, but not when compared with an active comparator gel containing propanediol, ornithine, phospholipids, and glycolipids (105909).
• Alopecia areata. Topical thyme oil has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study shows that applying a combination of the essential oils from thyme, rosemary, lavender, and cedarwood improves hair growth in up to 44% of patients after 7 months of treatment when compared with baseline (5177). The validity of this finding is limited by the lack of a comparator group. Additionally, it is unclear if this effect is due to thyme, other ingredients, or the combination.
• Bronchitis. Oral thyme has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some research has evaluated thyme in combination with cowslip. One observational study in adults and children has found that taking a specific product (Bronchipret) containing thyme and cowslip relieves symptoms of bronchitis and increases production of sputum (13557). A clinical study in patients with acute bronchitis shows that taking a similar combination extract (Bronchicum Tropfen) containing thyme and cowslip root 1 mL five times daily for 7-9 days seems to reduce severity and duration of coughing when compared with placebo (49219). Other thyme and cowslip preparations such as Bronchicum Elixir S and Bronchcium Tropfen seem to be similarly beneficial for bronchitis (49223). Thyme has also been studied in combination with other ingredients. A large clinical study in patients with acute bronchitis shows that taking a specific syrup (Bronchipret Saft, Bionorica AG) containing thyme and English ivy leaf 5.4 mL three times daily for 11 days reduces the frequency and duration of cough when compared with placebo (78152). Additionally, an observational study in children with acute bronchitis has found that taking this combination product in an age-specific dosing schema is associated with reduced bronchitis severity and coughing fits when compared to baseline (78181). However, due to the lack of a comparator group, it is unclear if these changes are due to the product or to the natural resolution of the condition.
• Colic. Although there is interest in using oral thyme for colic, there is insufficient reliable information about the clinical effects of thyme for this condition.
• Cough. Oral thyme has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A large open-label, uncontrolled study in adults with acute cough due to an upper respiratory tract infection who purchased a specific syrup (Bronchipret drops, Bionorica AG) containing thyme and English ivy leaf extracts suggests that taking this product as 2.6 mL three times daily for at least 4 days may improve patient-reported bronchitis symptom severity, cough severity, and quality of life, with over 90% of patients reporting overall satisfaction and product tolerability (110401). However, due to the lack of a comparator group, it is unclear if these changes are due to the product or the natural resolution of the condition. Additionally, the validity of these findings is limited by poor study methodology.
• Common cold. Although there is interest in using oral thyme for the common cold, there is insufficient reliable information about the clinical effects of thyme for this condition.
• Dementia. It is unclear if aromatherapy with thyme oil is beneficial in patients with dementia. Details: One very small clinical study in patients with advanced dementia shows that attaching a pad containing thyme oil to the collar area of the shirt does not reduce agitation when compared with lavender oil or unscented grapeseed oil (12213).
• Developmental coordination disorder (DCD). Oral thyme oil has only been evaluated in combination with other oils; its effect when used alone is unclear. Details: One very small clinical study in children with DCD shows that taking thyme oil, in combination with evening primrose oil, fish oil, and vitamin E (Efalex, Efamol Ltd.), seems to modestly improve movement disorders when compared with baseline (5708). The validity of this finding is limited by the lack of a comparator group. Additionally, it is unclear if this effect is due to thyme, other ingredients, or the combination.
• Dyspepsia. Although there is interest in using oral thyme for dyspepsia, there is insufficient reliable information about the clinical effects of thyme for this condition.
• Dysmenorrhea. It is unclear if drinking thyme tea is beneficial for the prevention of dysmenorrhea. Details: One small observational study in adolescents living in Ethiopia has found that drinking thyme tea is associated with a lower occurrence of primary dysmenorrhea when compared with those who did not drink thyme tea (105910).
• Halitosis. It is unclear whether oral thyme is beneficial for halitosis. Details: One small retrospective study in adults with gingival halitosis who received periodontal treatment and oral hygiene instructions suggests that drinking thyme tea twice daily for 1 week is associated with a reduction in volatile sulfur compounds, which is a marker for halitosis, when compared with chlorhexidine or oral hygiene alone (111716). However, the interpretation of this finding is limited by the lack of thyme dosing information and the narrow focus on intraoral halitosis, excluding most extraoral halitosis-associated conditions.
• Laryngitis. Although there is interest in using oral and topical thyme for laryngitis, there is insufficient reliable information about the clinical effects of thyme for this condition.
• Oral mucositis. Although there is interest in using oral and topical thyme for oral mucositis, there is insufficient reliable information about the clinical effects of thyme for this condition.
• Tonsillitis. Although there is interest in using oral and topical thyme for tonsillitis, there is insufficient reliable information about the clinical effects of thyme for this condition. More evidence is needed to rate thyme for these uses.

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LIKELY SAFE ...when peppermint oil is used orally, topically, or rectally in medicinal doses. Peppermint oil has been safely used in multiple clinical trials (3801,3804,6190,6740,6741,10075,12009,13413,14467,17681)(17682,68522,96344,96360,96361,96362,96363,96364,96365,99493).

POSSIBLY SAFE ...when peppermint leaf is used orally and appropriately, short-term. There is some clinical research showing that peppermint leaf can be used safely for up to 8 weeks (12724,13413). The long-term safety of peppermint leaf in medicinal doses is unknown. ...when peppermint oil is used by inhalation as aromatherapy (7107). There is insufficient reliable information available about the safety of using intranasal peppermint oil.

CHILDREN: POSSIBLY SAFE
when used orally for medicinal purposes. Enteric-coated peppermint oil capsules have been used with apparent safety under medical supervision in children 8 years of age and older (4469).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in amounts commonly found in foods (96361). There is insufficient information available about the safety of using peppermint in medicinal amounts during pregnancy or lactation; avoid using.

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LIKELY SAFE ...when used orally in amounts typically found in foods. Rosemary has Generally Recognized as Safe (GRAS) status in the US (4912).

POSSIBLY SAFE ...when the leaf is used orally and appropriately in medicinal amounts (18). Powdered rosemary leaf has been used with apparent safety as a single dose of up to 1.5 grams (18246,91731) or at a dose of 1-4 grams daily for up to 8 weeks (91727,98536,105327,109561). ...when the essential oil is used topically and appropriately for up to 7 months (5177,91729,109560). ...when the essential oil is used by inhalation as aromatherapy, short-term (7107,18323,105324,109559).

LIKELY UNSAFE ...when the essential oil or very large quantities of rosemary leaf are used orally. Ingestion of undiluted rosemary oil or very large quantities of rosemary leaf can cause serious adverse effects (18,515).

PREGNANCY: POSSIBLY UNSAFE
when used orally in medicinal amounts. Rosemary might have uterine and menstrual flow stimulant effects (4,12,18), and might increase metabolism of estradiol and estrone (18331); avoid using. There is insufficient reliable information available about the safety of rosemary when used topically during pregnancy.

LACTATION:
There is insufficient reliable information available about the safety of using rosemary in medicinal amounts during lactation; avoid using.

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LIKELY SAFE ...when used in amounts commonly found in foods. Thyme has Generally Recognized as Safe (GRAS) status in the US (4912).

POSSIBLY SAFE ...when thyme is used orally and appropriately in supplemental amounts. Orally, thyme, in combination with other herbs, has been used safely for up to 23 days (13557,49219,49223,78133). ...when diluted thyme oil is used topically, short-term. Diluted thyme oil has been used with apparent safety for up to 7 months (5177). There is insufficient reliable information available about the safety of thyme oil when used orally or when inhaled.

CHILDREN: LIKELY SAFE
when used in amounts commonly found in foods. Thyme has Generally Recognized as Safe (GRAS) status in the US (4912).

CHILDREN: POSSIBLY SAFE
when thyme is used orally in medicinal amounts in combination with English ivy. Thyme has been used with apparent safety in combination with English ivy for up to 10 days (78181). There is insufficient reliable information available about the safety of thyme oil when used orally or topically in children.

PREGNANCY AND LACTATION: LIKELY SAFE
when used in amounts commonly found in foods. Thyme has Generally Recognized as Safe (GRAS) status in the US (4912). There is insufficient reliable information available about the safety of thyme when used in medicinal amounts during pregnancy and breast-feeding; avoid using.

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CYCLOSPORINE (Neoral, Sandimmune) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, peppermint oil might increase the levels and adverse effects of cyclosporine.  Details In animal research, peppermint oil inhibits cyclosporine metabolism and increases cyclosporine levels. Inhibition of cytochrome P450 3A4 (CYP3A4) may be partially responsible for this interaction (11784). An interaction between peppermint oil and cyclosporine has not been reported in humans.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, peppermint might increase the levels of CYP1A2 substrates.  Details In vitro and animal research shows that peppermint oil and peppermint leaf inhibit CYP1A2 (12479,12734). However, in clinical research, peppermint tea did not significantly affect the metabolism of caffeine, a CYP1A2 substrate. It is possible that the 6-day duration of treatment may have been too short to identify a difference (96359).

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, peppermint might increase the levels of CYP2C19 substrates.  Details In vitro research shows that peppermint oil inhibits CYP2C19 (12479). So far, this interaction has not been reported in humans.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, peppermint might increase the levels of CYP2C9 substrates.  Details In vitro research shows that peppermint oil inhibits CYP2C9 (12479). So far, this interaction has not been reported in humans.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, peppermint might increase the levels of CYP3A4 substrates.  Details Clinical research in healthy volunteers shows that a single dose of peppermint oil 600 mg inhibits CYP3A4 enzymes and increases the AUC of felodipine, a CYP3A4 substrate (11783). However, in vitro research suggests that peppermint oil only inhibits CYP3A4 at very high concentrations (12479).

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ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, rosemary may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.  Details In vitro and animal research suggests that rosemary inhibits platelet aggregation (18334,18335,18336,18337).

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking rosemary with antidiabetes drugs might increase the risk of hypoglycemia.  Details Animal research shows that rosemary extract can decrease blood glucose levels in diabetic models (71821,71923). However, research in humans is conflicting. Although rosemary powder decreased blood glucose levels in healthy adults (105327), no change in blood glucose levels was seen in adults with type 2 diabetes, most of whom were taking antidiabetes drugs (105323,105327).

ASPIRIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, rosemary might have additive effects with salicylate-containing drugs such as aspirin.  Details Rosemary is reported to contain salicylates (18330).

CHOLINE MAGNESIUM TRISALICYLATE (Trilisate) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, rosemary might have additive effects with salicylate-containing drugs such as choline magnesium trisalicylate.  Details Rosemary is reported to contain salicylate (18330).

CYTOCHROME P450 1A1 (CYP1A1) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, rosemary might decrease the levels and clinical effects of CYP1A1 substrates.  Details In vitro research shows that rosemary induces CYP1A1 enzymes (18332,18333). This effect has not been reported in humans.

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, rosemary might decrease the levels and clinical effects of CYP1A2 substrates.  Details In vitro research shows that rosemary induces CYP1A2 enzymes (18332,18333). This effect has not been reported in humans.

SALSALATE (Disalcid) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, rosemary might have additive effects with salicylate-containing drugs such as salsalate.  Details Rosemary is reported to contain salicylate (18330).

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ANTICHOLINERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concurrent use of anticholinergic drugs and thyme essential oil might reduce the effects of anticholinergic drugs.  Details In vitro evidence suggests that thyme essential oil and specific essential oil constituents like thymohydroquinone and carvacrol can inhibit acetylcholinesterase (AChE) (78155). However, this effect has not been observed in humans.

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, thyme leaf extract might have additive effects with anticoagulant or antiplatelet drugs.  Details In vitro and animal research suggests that thyme leaf extract has antiplatelet effects (13457,18335,49445). However, this effect has not been observed in humans.

CHOLINERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concurrent use of cholinergic drugs and thyme essential oil might cause additive cholinergic effects.  Details In vitro evidence suggests that thyme essential oil and specific essential oil constituents like thymohydroquinone and carvacrol can inhibit acetylcholinesterase (AChE) (78155). However, this effect has not been observed in humans.

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, thyme might competitively inhibit the effects of estrogen replacement therapy.  Details In vitro research shows that thyme has estrogen receptor-binding activity and phytoestrogen content (3701). However, this effect has not been observed in humans.

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General ...Orally, topically, or rectally, peppermint oil is generally well tolerated. Inhaled, peppermint oil seems to be well tolerated. Intranasally, no adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted. Orally, peppermint leaf seems to be well tolerated.
Most Common Adverse Effects:
Orally: Abdominal pain, anal burning, belching, diarrhea, dry mouth, heartburn, nausea, and vomiting.
Topically: Burning, dermatitis, irritation, and redness.

Dermatologic ...Topically, peppermint oil can cause skin irritation, burning, erythema, and contact dermatitis (3802,11781,31528,43338,68473,68457,68509,96361,96362). Also, a case of severe mucosal injury has been reported for a patient who misused an undiluted over the counter mouthwash that contained peppermint and arnica oil in 70% alcohol (19106).
In large amounts, peppermint oil may cause chemical burns when used topically or orally. A case of multiple burns in the oral cavity and pharynx, along with edema of the lips, tongue, uvula, and soft palate, has been reported for a 49-year-old female who ingested 40 drops of pure peppermint oil. Following treatment with intravenous steroids and antibiotics, the patient's symptoms resolved over the course of 2 weeks (68432). Also, a case of chemical burns on the skin and skin necrosis has been reported for a 35-year-old male who spilled undiluted peppermint oil on a previous skin graft (68572). Oral peppermint oil has also been associated with burning mouth syndrome and chronic mouth ulceration in people with contact sensitivity to peppermint (6743). Also, excessive consumption of mint candies containing peppermint oil has been linked to cases of stomatitis (13114).

Gastrointestinal ...Orally, peppermint oil can cause heartburn, nausea and vomiting, anal or perianal burning, abdominal pain, belching, dry mouth, diarrhea, and increased appetite (3803,6740,6741,6742,10075,11779,11789,17682,68497,68514)(68532,68544,96344,96360,102602,104219,107955). Enteric-coated capsules might help to reduce the incidence of heartburn (3802,4469,6740,11777). However, in one clinical study, a specific enteric-coated formulation of peppermint oil (Pepogest; Nature's Way) taken as 180 mg three times daily was associated with a higher rate of adverse effects when compared with placebo (48% versus 31%, respectively). Specifically, of the patients consuming this product, 11% experienced belching and 26% experienced heartburn, compared to 2% and 12%, respectively, in the placebo group (107955). A meta-analysis of eight small clinical studies in patients with irritable bowel syndrome shows that taking enteric-coated formulations of peppermint oil increases the risk of gastroesophageal reflux symptoms by 67% when compared with a control group (109980). Enteric-coated capsules can also cause anal burning in people with reduced bowel transit time (11782,11789).

Genitourinary ...Orally, a sensitive urethra has been reported rarely (102602).

Hepatic ...One case of hepatocellular liver injury has been reported following the oral use of peppermint. Symptoms included elevated liver enzymes, fatigue, jaundice, dark urine, and signs of hypersensitivity. Details on the dosage and type of peppermint consumed were unavailable (96358).

Immunologic ...One case of IgE-mediated anaphylaxis, characterized by sudden onset of lip and tongue swelling, tightness of throat, and shortness of breath, has been reported in a 69-year-old male who consumed peppermint candy (89479). An allergic reaction after use of peppermint oil in combination with caraway oil has been reported in a patient with a history of bronchial asthma (96344). It is not clear if this reaction occurred in response to the peppermint or caraway components.

Neurologic/CNS ...Orally, headache has been reported rarely (102602).

Ocular/Otic ...Orally, peppermint has been reported to cause blurry vision (3803).

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General ...Orally, rosemary seems to be well tolerated when used in appropriate medicinal amounts. Undiluted rosemary oil or very large quantities of rosemary leaf should not be consumed. Topically and as aromatherapy, rosemary seems to be well tolerated.

Dermatologic ...Topically, rosemary use can lead to photosensitivity, erythema, dermatitis, and cheilitis in hypersensitive individuals (4,6).

Immunologic ...Topically, allergic reactions can occur. When used in the mouth, lip and gum edema have occurred (101173). When used on the skin, allergic contact dermatitis has occurred, likely due to the constituent carnosol (71715,71924,71926).
Rosemary might also cause occupational asthma. A case of occupational asthma caused by several aromatic herbs including thyme, rosemary, bay leaf, and garlic has been reported. The diagnosis was confirmed by inhalation challenges. Although all of the herbs caused immediate skin reactivity, a radioallergosorbent test (RAST) showed that garlic was the most potent allergen by weight, with rosemary and the other herbs showing less reactivity (783).

Neurologic/CNS ...Orally, the undiluted oil, as well as the camphor constituent of rosemary, might cause seizures (4,5,6,12868).

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General ...Orally, thyme is well tolerated when used in food and seems to be well tolerated when used medicinally. Topically, thyme seems to be generally well tolerated.
Most Common Adverse Effects:
Orally: Allergic reactions, diarrhea, dizziness, headache, heartburn, nausea, or vomiting.
Topically: Contact dermatitis and skin irritation.

Dermatologic ...Topically, thyme, thyme oil, or the constituent thymol can cause contact dermatitis and skin irritation (13463,78252,78362,78384,77982,78154,78310,78313,78384). In one study of 100 patients with contact allergies, 5% were attributed to thyme oil as an allergen contained in wound dressings (78362). Toothpastes containing thymol have been associated with cheilitis and glossitis (13463).

Gastrointestinal ...Orally, thyme and thyme oil may cause heartburn, nausea, vomiting, stomach upset, or diarrhea (13557,94033). In a clinical study, two patients using extracts of thyme herb and ivy leaves experienced temporary stomach ache and mild nausea (78181).
Intravaginally, cream containing thyme and garlic has been associated with reports of nausea and vomiting in one clinical study (88387). It is not clear if these adverse effects were associated with thyme, garlic, or the combination.

Genitourinary ...Intravaginally, cream containing thyme and garlic has been associated with reports of vaginal dryness and vaginal irritation in one clinical study (88387). It is not clear if these adverse effects were associated with thyme, garlic, or the combination.

Immunologic ...Orally, thyme can cause allergic reactions; however, this is uncommon (13463). Allergic reactions to thyme might be more common in people who are also allergic to oregano and other Lamiaceae species (3808).

Neurologic/CNS ...Orally, thyme may case headache or dizziness (94033).

Pulmonary/Respiratory ...By inhalation, occupational exposure to thyme dust can cause acute airway obstruction (783,13463,13464,77982,78098).

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