Saccharomyces Boulardii
Saccharomyces boulardii
A beneficial probiotic yeast that supports gut health, prevents traveler's diarrhea, and protects against antibiotic-associated digestive issues.
Saccharomyces boulardii is a beneficial yeast (not a bacteria) that acts as a probiotic. Unlike bacterial probiotics, it's resistant to antibiotics, making it ideal to take alongside antibiotic therapy to prevent diarrhea. It's also highly effective for traveler's diarrhea prevention and treating acute infectious diarrhea. S. boulardii also shows promise for inflammatory bowel conditions.
Mechanisms of Action
Pathogen Binding
Binds to harmful bacteria and removes them
Immune Modulation
Balances intestinal immune response
Gut Barrier Support
Helps maintain intestinal barrier integrity
Recommended Dose
250-500mg (5-10 billion CFU) daily
Loading: For acute diarrhea, may use 500mg 2x daily
Optimal Timing
- With or without food
- At least 2 hours away from antifungals
Can be taken without food
Best Form
Capsules (lyophilized)
Alternatives: Powder, Sachets
Look for products with verified CFU counts. CNCM I-745 is the most researched strain (Florastor brand).
Duration
Minimum: 1 weeks
Optimal: 4 weeks
Cycling: Not required
Note: As a yeast, it's not killed by antibiotics. Start 2 days before travel for prevention. Continue 1 week after antibiotics finish.
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Diarrhea Prevention
Prevents antibiotic-associated and traveler's diarrhea
Acute Diarrhea Treatment
Reduces duration of acute infectious diarrhea
Gut Microbiome Support
Helps restore healthy gut flora after antibiotics
Avoid; risk of fungemia
Well-studied and safe for pediatric diarrhea
Who Should NOT Take This
- Central venous catheter (risk of fungemia)
- Severely immunocompromised
- ICU patients
Drug Interactions
Antifungals will kill S. boulardii - separate by 2+ hours
Possible Side Effects
Tip: Usually transient
Warnings
- Do not use with central venous catheters
- Avoid in severely immunocompromised patients
Top studies from 40+ peer-reviewed papers
McFarland LV et al. ā¢ Frontiers in cellular and infection microbiology (2025)
āS. boulardii CNCM I-745 is an effective treatment for PAGE and was well tolerated in trials done in China.ā
Key Findings:
- S. boulardii CNCM I-745 was found to significantly reduce the duration of PAGE (SMD=-1.63 days, 95% CI -2.08, -1.18), improve the total effectiveness rating (RR=1.22, 95% CI 1.16, 1.28) and significantly more participants were cured (RR=1.47, 95% CI 1.30, 1.67).
- The finding that S. boulardii significantly reduced the levels of two pro-inflammatory cytokines (TNF-Ī± and IL8) has not been reported in previous meta-analyses of PAGE.
- S. boulardii CNCM I-745 is an effective treatment for PAGE and was well tolerated in trials done in China.
Li M et al. ā¢ Frontiers in cellular and infection microbiology (2025)
āS. boulardii supplementation in traditional eradication therapy significantly improves the H. pylori eradication rate and reduces the total adverse effects and incidence of diarrhea, bloating, constipation, and nausea.ā
Key Findings:
- S. boulardii supplementation in traditional eradication therapy significantly improves the H. pylori eradication rate and reduces the total adverse effects and incidence of diarrhea, bloating, constipation, and nausea.
- Published in Frontiers in cellular and infection microbiology (2025)
- Further research warranted to confirm findings
Li Z et al. ā¢ Nutrients (2021)
āTo be conclusive, Saccharomyces boulardii may be the most effective probiotic for treating acute diarrhea in children, followed by several other single-strain and multi-strain probiotics.ā
Key Findings:
- Saccharomyces boulardii [Odds ratio (OR) = 0.22; 95%CI, 0.11, 0.41] and Lactobacillus reuteri (OR = 0.23; 95%CI, 0.090, 0.60) significantly reduced the risk of diarrhea lasting ā„2 days when compared with placebo or no treatment, with moderate evidence.
- To be conclusive, Saccharomyces boulardii may be the most effective probiotic for treating acute diarrhea in children, followed by several other single-strain and multi-strain probiotics.
- Further research warranted to confirm findings
Collinson S et al. ā¢ The Cochrane database of systematic reviews (2020)
āProbiotics probably make little or no difference to the number of people who have diarrhoea lasting 48 hours or longer, and we are uncertain whether probiotics reduce the duration of diarrhoea.ā
Key Findings:
- Effect size was similar in the sensitivity analysis and marked heterogeneity persisted.
- Effect size was similar and marked heterogeneity persisted in pre-specified subgroup analyses of the primary outcomes that included all studies.
- In six trials (433 participants) of Lactobacillus reuteri, there was consistency amongst findings (IĀ² = 0%), but risk of bias was present in all included studies.
- In addition, there were no clear differences in effect size for the primary outcomes in post hoc analyses according to decade of publication of studies and whether or not trials had been registered.
Rahman MN et al. ā¢ Gut microbes (2024)
āProtocol registration: PROSPERO (ID = CRD42021276045).ā
Key Findings:
- This review aims to analyze available evidence from human-controlled trials to determine the effect size of probiotic interventions in decolonizing AMR pathogenic bacteria from the gut.
- The persistence of pathogenic bacteria after treatment was 22%(probiotics) and 30.8%(placebo).
- The pooled odds ratio was 0.59(95% CI:0.43-0.81), favoring probiotics with moderate certainty (pā=ā0.0001) and low heterogeneity (I2ā=ā49.2%, pā=ā0.0001).
- In subgroup, C. difficile showed the highest decolonization (82.4%) in probiotics group.
Study Type Distribution
Goals This Supplement Supports
Related Goals
This information is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider before starting any supplement.