March 2020

Probiotics: What Works and What Doesn’t

Probiotics are promoted for a long list of unproven uses. While many claimed benefits aren’t supported by scientific evidence, don’t forget that some are. But not all probiotics have the same effects. So which probiotics work, and what do they work for?

When it comes to treating and preventing diarrhea, tell patients that the best evidence is for Saccharomyces boulardii. It reduces the duration of diarrhea in infants and kids, including diarrhea from rotavirus, by about 12 to 24 hours. But keep in mind that it doesn’t seem to be as effective as conventional drugs such as loperamide (Imodium). Research also shows that Saccharomyces boulardii can prevent diarrhea in people with feeding tubes.

Patients may also ask about using probiotics for antibiotic-associated diarrhea. Tell patients that overall, taking a lactobacillus-containing probiotic reduces the risk of antibiotic-associated diarrhea by about 36% to 70%. Lactobacillus GG (Culturelle) is the best studied lactobacillus strain for this use. Saccharomyces boulardii also seems to help. It can lower diarrhea risk by 52% to 63%. Evidence on most other probiotic species and combination products is mixed.

Probiotics are also promising for treating and preventing eczema. Most research shows that taking probiotics reduces symptoms in infants and kids. Taking probiotics during pregnancy might also lower the chance of the baby developing eczema. For now, the best evidence is for lactobacillus strains, but it’s unclear if this is the most effective species or whether certain lactobacillus strains might work better than others.

There are many other proposed uses for probiotics, some of which have evidence suggesting benefit. For more details on which probiotics might benefit certain conditions, check out our NEW Probiotics monograph. To drill down on the research for specific species and strains, including important safety and dosing data, review our monographs on LactobacillusBifidobacteriaSaccharomyces boulardiiBacillus CoagulansBrewer’s YeastKefir, and Yogurt. Keep in mind that not all species, strains, or combinations have been thoroughly studied. It’s important to identify the specific species and strains in a given product in order to weigh its pros and cons. And although probiotics are likely safe when used appropriately, they might not be a safe option for everyone, particularly people with weakened immune systems or certain conditions.

The information in this brief report is intended for informational purposes only, and is meant to help users better understand health concerns. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions. Copyright © 2024 NatMed. Commercial distribution or reproduction prohibited. NatMed is the leading provider of high-quality, evidence-based, clinically-relevant information on natural medicine, dietary supplements, herbs, vitamins, minerals, functional foods, diets, complementary practices, CAM modalities, exercises and medical conditions. Monograph sections include interactions with herbs, drugs, foods and labs, contraindications, depletions, dosing, toxicology, adverse effects, pregnancy and lactation data, synonyms, safety and effectiveness.