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Moderate evidenceGut health

Probiotics

Live microorganisms with strain-specific effects. Best evidence: preventing antibiotic-associated diarrhea. For everything else, results depend heavily on the strain.

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What the science says

  • Preventing antibiotic-associated diarrhea Moderate evidence

    A meta-analysis of 63 randomized trials found probiotics reduced the risk of antibiotic-associated diarrhea by about 42%. Strains of Lactobacillus rhamnosus GG and Saccharomyces boulardii have the most support.

  • General 'gut health' in healthy people Limited evidence

    For people without a specific condition, evidence of meaningful benefit is weak. Effects are strain- and condition-specific — a generic probiotic is not guaranteed to do anything.

Dosage & safety

Studied doseTypically 1–10 billion CFU/day of a studied strain, taken during and after antibiotic courses for the best-supported use.
SafetySafe for healthy people. Avoid in severely immunocompromised patients without medical supervision.

How to take it

TimingKeep at least 2 hours between the probiotic and any antibiotic dose; otherwise timing does not matter.
With food?With or just before a meal — food buffers stomach acid and more organisms survive to the intestine.
Worth knowingMatch the strain to the claim: benefits are strain-specific, so a product that lists only 'Lactobacillus blend' with no strain codes is untested for whatever you bought it for.

Interactions

With medications

  • antibiotics

    The antibiotic kills the bacteria in the capsule if they are taken together. separate by at least 2 hours and continue the probiotic for 1-2 weeks after the course ends

  • immunosuppressants and chemotherapy

    Live organisms have caused bloodstream infection in severely immunocompromised patients. do not use without your treating team's approval

  • antifungals (fluconazole, nystatin)

    Saccharomyces boulardii is a yeast and is killed by antifungal drugs. choose a bacterial strain instead while on antifungal treatment

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Do probiotics prevent diarrhea from antibiotics?

This is the best-supported use of probiotics, with moderate evidence: a meta-analysis of 63 trials found about a 42% lower risk of antibiotic-associated diarrhea. Lactobacillus rhamnosus GG and Saccharomyces boulardii have the most support.

Are probiotics worth taking for gut health?

For healthy people without a specific condition, the evidence for probiotics is limited. Probiotic effects depend on the strain, so a generic blend with no strain codes is untested for whatever you bought it for.

When should I take probiotics with antibiotics?

Keep probiotics at least 2 hours away from any antibiotic dose, because the antibiotic kills the bacteria in the capsule. Continue the probiotic for 1–2 weeks after the course ends.

Are probiotics safe for everyone?

Probiotics are safe for healthy people, but live organisms have caused bloodstream infections in severely immunocompromised patients. If you are on immunosuppressants or chemotherapy, use probiotics only with your treating team's approval.

Scientific references

Where to buy

California Gold Nutrition, LactoBif® 30 Probiotics, 60 Veggie Capsules

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