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saccharomyces boulardii

What does the research say about saccharomyces boulardii?

9 health outcomes synthesised

Saccharomyces boulardii, a probiotic yeast, has been studied across nine health outcomes, with the strongest and most consistent evidence supporting its use for reducing diarrhea. In a synthesis of nine studies, all reported beneficial effects, predominantly with a moderate effect size, in clinical populations such as patients undergoing antibiotic therapy or radiotherapy. The most studied doses range from 250 mg to 500 mg four times daily, though most research is limited to short-term use of around 14 days.

Strongest evidence: The most robust research supports Saccharomyces boulardii for reducing diarrhea, with all 9 studies reporting benefit (moderate effect size, high evidence strength) in populations including patients with H. pylori infection, those on antibiotics, and critically ill tube-fed patients. Doses in these studies ranged from 250 mg/day to 500 mg four times daily. Additional moderate-strength evidence from 10 studies shows benefit for reducing diarrhea rate (8 of 10 beneficial, moderate effect), primarily in children with acute gastroenteritis, with doses of 250–500 mg/day common. Moderate evidence also supports benefit for reducing constipation (3 of 3 studies, large effect) and reducing abdominal distension (3 of 3 studies, large effect) in H. pylori patients, though the evidence base is small.

Mixed or weaker evidence: For improved H. pylori eradication rates, the evidence is mixed: 5 of 8 studies showed benefit, but 3 were neutral, with effect sizes ranging from small to large (moderate evidence strength). Similarly, increased H. pylori eradication rate (a related outcome) showed benefit in 4 of 5 studies, but effect sizes were small and doses inconsistent. For reduced abdominal pain, 5 of 6 studies reported benefit, but effect sizes varied widely (mixed). Reduced duration of diarrhea showed benefit in 3 of 4 studies, but a meta-analysis found a neutral result, and the evidence base is small. Reduced stool frequency in children with acute diarrhea showed benefit in all 3 studies (moderate effect), but the evidence is preliminary.

Effective dose patterns: Across outcomes, the most frequently reported effective dose range is 250–500 mg/day, with some studies using up to 500 mg four times daily (for severe diarrhea in clinical settings). No consistent dose was reported for abdominal pain, constipation, or abdominal distension, limiting dose-response conclusions.

Population insights: The strongest evidence comes from clinical populations—particularly patients with H. pylori infection, hospitalized patients on antibiotics, and children with acute gastroenteritis. Generalizability to healthy individuals or chronic conditions remains uncertain. Most studies were short-term (median 14–60 days), and long-term effects are not well studied.

Notable caveats: Across syntheses, publication bias is a major concern, as null results are less likely to be published. Many studies did not consistently report dose, form, or duration, and several outcomes rely on small numbers of studies (3–4 papers), making conclusions preliminary. Evidence for outcomes like constipation and abdominal distension comes exclusively from H. pylori patients and may not generalize.

Frequently asked

  • What is saccharomyces boulardii good for according to research?
    Research shows Saccharomyces boulardii is most consistently beneficial for reducing diarrhea. Across 9 studies, all reported beneficial effects, primarily in patients on antibiotics, undergoing radiotherapy, or with H. pylori infection. Moderate evidence also supports benefits for reducing constipation, abdominal distension, and diarrhea rate in specific populations.
  • What dose of saccharomyces boulardii is typically used in studies?
    The most common dose range reported across studies is 250–500 mg per day. For reducing diarrhea, doses up to 500 mg four times daily have been used. However, many studies did not consistently report dose or supplement form, so a clear dose-response relationship cannot be determined.
  • Who benefits most from saccharomyces boulardii?
    The strongest evidence comes from clinical populations: patients with H. pylori infection, hospitalized patients on antibiotics, children with acute gastroenteritis, and patients undergoing pelvic radiotherapy. Generalizability to healthy individuals or those with chronic digestive issues is uncertain due to limited research in those groups.
  • Are there caveats or limitations in the research on saccharomyces boulardii?
    Yes. Publication bias is a major concern, as studies with null results are less likely to be published. Many studies did not report dose, duration, or supplement form consistently. Several outcomes are based on small numbers of studies (3–4), making findings preliminary. Most research is also short-term (14–60 days) and focused on specific populations, limiting broader conclusions.
  • Does saccharomyces boulardii help with H. pylori eradication?
    Evidence is mixed. Of 8 studies, 5 reported benefit for improving H. pylori eradication rates, but 3 found no significant effect, and effect sizes varied from small to large. A 2025 meta-analysis of 11 RCTs showed a 12% relative improvement in eradication rates when used as an adjunct to standard therapy, but the effect is modest.
  • What is the evidence for saccharomyces boulardii on constipation or abdominal distension?
    Evidence is preliminary but positive. All 3 studies on constipation and all 3 on abdominal distension reported large beneficial effects, but all were conducted in H. pylori patients, so results may not generalize to other causes. The evidence base is small, and conclusions should be considered preliminary.

Most-studied combinations with saccharomyces boulardii

most supplement research is combination research
Also studied with:Lactobacillus rhamnosus GG (2)
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