Big effect
Adding saccharomyces boulardii to H. pylori therapy slashed diarrhea risk by 72% — but the benefit comes from a meta-analysis of a clinical population on antibiotics, not casual use.
This is a large, statistically robust effect in people already taking a harsh antibiotic cocktail, supported by 8 out of 10 studies showing benefit, but the evidence is only moderate overall and doesn't address whether the same reduction would occur in healthy people taking the yeast on its own.
A meta-analysis of 10 studies found that people taking saccharomyces boulardii alongside bismuth quadruple therapy for H. pylori were nearly three-quarters less likely to get diarrhea (risk ratio 0.28). The effect was strongest at 500 mg/day for more than 10 days, but the results come from a sick population on multiple antibiotics, so it's not clear how well they generalize to everyday digestive health. The same study also noted that the yeast group had fewer other side effects like nausea and bloating, though the funding source and blinding were not reported.
Where this fits in the evidence
Pillser has synthesized 10 studies on saccharomyces boulardii for Reduced Diarrhea Rate — overall evidence strength: Moderate.
Across 10 studies, 8 reported beneficial effects of Saccharomyces boulardii on reducing diarrhea rates, with 2 showing neutral findings and none harmful. Effect sizes ranged from small to large, with a moderate effect size most common. The evidence primarily comes from children with acute gastroenteritis or Helicobacter pylori infection, with a median study duration of 60 days reported in one study. Most studies did not specify a consistent dose, though doses of 250 mg to 500 mg/day appeared frequently.
The study
- Meta-Analysis
- 2025-04-18
- BMC gastroenterology
This is a plain-language summary of a research finding, not medical advice. Pillser surfaces research signals to help you decide what's worth investigating — always consult a qualified professional before changing what you take.