Below is general information about the effectiveness of the known ingredients contained in the product Comfrey/Aloe Capsules. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
Below is general information about the safety of the known ingredients contained in the product Comfrey/Aloe Capsules. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
LIKELY SAFE ...when aloe gel is used topically and appropriately. Aloe gel-containing formulations have been safely applied in clinical trials (101,11982,12096,12098,12159,12160,12163,12164,17418)(90123,90124,90127,90128,90129,90131,97320,98816,103305). When included in topical cosmetics, the Cosmetic Ingredient Review Expert Panel concluded that aloe-derived anthraquinone levels should not exceed 50 ppm (90122).
POSSIBLY SAFE ...when aloe gel is used orally and appropriately, short-term. Aloe gel has been safely used in a dose of 15 mL daily for up to 42 days or 100 mL of a 50% solution twice daily for up to 4 weeks (11984,12164). Also, a specific aloe gel complex (Aloe QDM complex, Univera Inc.) has been safely used at a dose of approximately 600 mg daily for up to 8 weeks (90121). ...when aloe extract is used orally and appropriately, short-term. Aloe extract has been used with apparent safety in a dose of 500 mg daily for one month (101579). Also, an aloe extract enriched in aloe sterols has been used with apparent safety in a dose of 500 mg daily for 12 weeks (101577).
POSSIBLY UNSAFE ...when aloe latex is used orally. There is some evidence that anthraquinones in aloe latex are carcinogenic or promote tumor growth, although data are conflicting (6138,16387,16388,91596,91597). In 2002, the US FDA banned the use of aloe latex in laxative products due to the lack of safety data (8229). ...when aloe whole-leaf extract is used orally. Aloe whole-leaf extract that has not been filtered over charcoal still contains anthraquinones. This type of aloe whole-leaf extract is referred to as being "nondecolorized". The International Agency for Research on Cancer has classified this type of aloe whole-leaf extract as a possible human carcinogen (91598,91908). Although filtering aloe whole-leaf extract over charcoal removes the anthraquinones, some animal research suggests that this filtered extract, which is referred to as being "decolorized", may still cause gene mutations (91598). This suggests that constituents besides anthraquinones may be responsible for the carcinogenicity of aloe whole-leaf extract. It should be noted that commercial products that contain aloe whole-leaf extract may be labeled as containing "whole leaf Aloe vera juice" or "aloe juice" (91908).
LIKELY UNSAFE ...when aloe latex is used orally in high doses. Ingesting aloe latex 1 gram daily for several days can cause nephritis, acute kidney failure, and death (8,8961).
CHILDREN: POSSIBLY SAFE
when aloe gel is used topically and appropriately.
Aloe gel-containing formulations have been safely applied in clinical trials (90124,90131).
CHILDREN: POSSIBLY UNSAFE
when aloe latex and aloe whole leaf extracts are used orally in children.
Children younger than 12 years may experience abdominal pain, cramps, and diarrhea (4).
PREGNANCY: POSSIBLY UNSAFE
when used orally.
Anthraquinones present in aloe latex and aloe whole leaf extracts have irritant, cathartic, and possible mutagenic effects (4,16387,16388,90122). There are also anecdotal reports and evidence from animal research that anthraquinones or aloe whole leaf extracts might induce abortion and stimulate menstruation; avoid using (4,8,19,90122).
LACTATION: POSSIBLY UNSAFE
when aloe preparations are used orally.
Cathartic and mutagenic anthraquinones present in aloe latex and aloe whole leaf extracts might pass into milk; avoid using (4,19).
POSSIBLY SAFE ...when used topically for less than 6 weeks on unbroken skin at a daily dose providing no more than 100 mcg of pyrrolizidine alkaloid (PA) constituents. PAs are absorbed through the skin (11990,44898,44902,92568).
POSSIBLY UNSAFE ...when used for extended durations or in high concentrations on unbroken skin. Topically, hepatotoxic pyrrolizidine alkaloids (PAs) in comfrey can be absorbed in quantities sufficient to cause toxicity with extended use for greater than 6 weeks or in quantities providing more than 100 mcg of PAs (11990,92568). ...when used topically on broken skin. PAs can be absorbed through broken skin. In countries where the PA content of comfrey is not regulated, including Australia and the United States, creams containing comfrey are required to include a warning not to use on broken skin (44950,44951).
LIKELY UNSAFE ...when used orally because of its potential for acute or chronic liver toxicity. Comfrey contains hepatotoxic pyrrolizidine alkaloids (PAs). Chronic ingestion of more than 1 mg daily for 2 weeks or more than 100 mcg daily for longer durations can cause liver disease. PAs may also be carcinogenic (11987,99068). The FDA has recommended removal of oral comfrey products from the market (11988).
PREGNANCY AND LACTATION: LIKELY UNSAFE
when used orally or topically.
In addition to hepatotoxicity and possible carcinogenicity, the pyrrolizidine alkaloids (PAs) in comfrey might be teratogenic. PAs are absorbed through the skin (11987,11988,11990).
Below is general information about the interactions of the known ingredients contained in the product Comfrey/Aloe Capsules. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
Theoretically, aloe gel might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.
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In vitro research shows that aloe gel can inhibit platelet aggregation. This inhibition was greater than that seen with celecoxib, but less than that seen with aspirin (105501).
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Aloe might increase the risk of hypoglycemia when taken with antidiabetes drugs.
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Theoretically, aloe latex might increase the risk of adverse effects when taken with cardiac glycosides.
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Overuse of aloe latex can increase the risk of adverse effects from cardiac glycoside drugs, such as digoxin, due to potassium depletion. Overuse of aloe, along with cardiac glycoside drugs, can increase the risk of toxicity (19).
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Theoretically, aloe latex might increase the risk of hypokalemia when taken with diuretic drugs.
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Overuse of aloe latex might compound diuretic-induced potassium loss, increasing the risk of hypokalemia (19).
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Theoretically, aloe latex might increase the risk for fluid and electrolyte loss when taken with stimulant laxatives.
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Theoretically, aloe latex might increase the risk of bleeding when taken with warfarin.
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Aloe latex has stimulant laxative effects. In some people aloe latex can cause diarrhea. Diarrhea can increase the effects of warfarin, increase international normalized ratio (INR), and increase the risk of bleeding. Advise patients who take warfarin not to take excessive amounts of aloe vera.
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Theoretically, CYP3A4 inducers might increase the risk of adverse effects from the pyrrolizidine alkaloid constituents in comfrey.
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Theoretically, comfrey might have additive adverse effects on the liver when used with hepatotoxic drugs.
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Below is general information about the adverse effects of the known ingredients contained in the product Comfrey/Aloe Capsules. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
General
...Orally and topically, aloe products are generally well tolerated when used in typical doses.
However, oral aloe latex is associated with a greater risk of adverse effects, especially when used in high doses or long-term.
Most Common Adverse Effects:
Orally: Aloe latex may cause abdominal pain, cramps, and diarrhea.
Topically: Burning, erythema, and itching. Contact dermatitis in sensitive individuals.
Serious Adverse Effects (Rare):
Orally: Aloe latex is associated with serious adverse effects when taken in high doses or long-term. Cases of acute hepatitis due to a hypersensitivity reaction to aloe leaf extract has been reported.
Dermatologic ...Topically, aloe gel has occasionally been associated with burning (12164,19741,30697,30706), itching (12164,19741,30697), eczema (90122), erythema (19748,30706,90123), contact dermatitis (12163,12164,30695,30736,30737,30738,30740), popular eruption (30732), and urticaria (30712). Also, a case of generalized nummular and popular dermatitis attributed to hypersensitivity has been reported for a 47-year-old male who used aloe leaf gel, both topically and orally, for 4 years (30740).
Endocrine ...A case of severe hypokalemia has been reported for a male breast cancer patient who was undergoing chemotherapy and using aloe vera 1 liter daily orally for 2 weeks. The hypokalemia was attributed to the cathartic effects of aloe and resolved once aloe use was discontinued (30704).
Gastrointestinal
...Orally, aloe latex can cause abdominal pain and cramps.
Long-term use or abuse of aloe latex can cause diarrhea, sometimes with hypokalemia, albuminuria, hematuria, muscle weakness, weight loss, arrhythmia, and pseudomelanosis coli (pigment spots in intestinal mucosa). Pseudomelanosis coli is believed to be harmless, and usually reverses with discontinuation of aloe. It is not directly associated with an increased risk of developing colorectal adenoma or carcinoma (6138). Orally, aloe gel may cause nausea, stomach cramps, and other gastrointestinal complaints in some patients (104174,111921,111663).
Topically, applying aloe gel in the mouth may cause nausea within 5 minutes of application in some patients (90124).
Hematologic ...A case of Henoch-Schonlein purpura, characterized by abdominal pain, purpura, and severe arthralgia, has been reported in a 52-year-old male who drank aloe juice prepared from four to five leaflets for 10 days prior to symptom development (91598).
Hepatic ...Cases of acute hepatitis have been reported after ingestion of aloe leaf extracts for between 3 weeks and 5 years. This is thought to be a hypersensitivity reaction (15567,15569,16386,17419,90126,91598). A case of acute hepatitis has also been reported for a 45-year-old female who drank two ounces of Euforia juice (Nuverus International), a product containing green tea, noni, goji, and aloe, daily for one month (90125). However, one small clinical trial in healthy individuals shows that taking aloe gel 2 ounces twice daily for 60 days does not impair liver function (104174).
Renal ...Orally, aloe latex can cause hemorrhagic gastritis, nephritis, and acute kidney failure following prolonged use of high doses (1 gram daily or more) (8961).
General
...When used orally, comfrey may be unsafe.
Topically, comfrey is generally well tolerated when applied to intact skin.
Most Common Adverse Effects:
Topically: Eczema, erythema, irritation, itching, rash.
Serious Adverse Effects (Rare):
All ROAs: Ascites, cirrhosis, death, hepatic fibrosis, hepatomegaly, pulmonary hypertension, and sinusoidal obstruction syndrome. These adverse effects are likely related to the pyrrolizidine alkaloid constituents of comfrey.
Dermatologic ...Topically, comfrey-containing creams and ointments may cause skin redness, irritation, itching, rash, and eczema (44902,44912,44917,44919,92566,92570,92571).
Hepatic ...The pyrrolizidine alkaloid constituents of comfrey can cause acute sinusoidal obstruction syndrome characterized by sudden abdominal pain, vomiting, ascites, and hepatomegaly. In subacute disease, comfrey can cause ascites, hepatomegaly, abdominal pain, diarrhea, vomiting, and abdominal swelling. Chronic toxicity appears as asthenia and progressive ascites. Hepatic fibrosis and inflammation may resolve, but hepatic failure is common with more severe disease. This may occur as late as 2 years after the initial ingestion. Other signs and symptoms of pyrrolizidine toxicity include bile duct proliferation, fatty changes of the liver, fibrosis, cirrhosis, and vascular lesions (11988). The mortality associated with comfrey toxicity is 50%. However, specific toxic levels seem to vary among individuals (11990).
Pulmonary/Respiratory ...The pyrrolizidine alkaloid constituents of comfrey can damage the lungs, resulting in pulmonary hypertension (11987,11988,11990). A case report involving a 66-year-old female with known arterial hypertension, mild kidney insufficiency, and type 2 diabetes described severe partial respiratory insufficiency and pulmonary hypertension. The patient admitted to using a number of alternative therapies daily, including comfrey (44911).
Other ...Comfrey contains toxic pyrrolizidine alkaloids, which are carcinogenic and mutagenic (12841,12842).