Big effect
A meta-analysis of 10 Chinese pediatric trials found that Saccharomyces boulardii shortened diarrhea by about 1.6 days — in children already receiving standard care.
This is an unusually large effect for a probiotic in acute diarrhea, but it comes from studies in a specific clinical population (hospitalized children in China), and the underlying trials don't appear to have been blinded — so the real-world benefit for adults or for milder cases could be smaller.
Analyzing 10 randomized trials involving 1,125 children with acute gastroenteritis, researchers found that adding Saccharomyces boulardii CNCM I-745 to standard treatment cut diarrhea duration by roughly 1.6 days on average. The yeast also improved treatment response and cure rates while lowering a marker of inflammation (TNF-alpha). However, the included studies were conducted entirely in Chinese clinical settings without reported blinding, which limits how broadly the results apply.
Where this fits in the evidence
Pillser has synthesized 3 studies on Saccharomyces boulardii for Reduced Duration of Diarrhea — overall evidence strength: Moderate.
Across 3 studies, all reported beneficial effects on reducing diarrhea duration, with effect sizes ranging from small to large. The strongest evidence (a meta-analysis of 1125 children) showed a large effect (reduction of ~1.6 days). The evidence base is small and primarily limited to pediatric populations with acute gastroenteritis; dosing information was not consistently reported.
The study
- Meta-Analysis
- n = 1,125
- 2025-06-04
- Frontiers in cellular and infection microbiology
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.