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Saccharomyces boulardii
Antibiotic-resistant probiotic yeast ideal for preventing traveler's diarrhea and protecting gut flora during antibiotic therapy.
What the evidence says
Saccharomyces Boulardii appears to help in 12 of 14 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2005–2025 with a typical study size of 156 participants.
Based on 27 studies · 14 meta-analyses · 8 RCTs · 52,732 total participants
Confidence
HighWhat the studies found
By outcome
Saccharomyces Boulardii has an evidence score of 9/10 — very strong evidence based on 27 indexed studies, including 26 meta-analyses. Antibiotic-resistant probiotic yeast ideal for preventing traveler's diarrhea and protecting gut flora during antibiotic therapy.
The commonly studied dose of Saccharomyces Boulardii is 250-500mg (5-10 billion CFU) daily. Research points to an estimated optimal dose around 10mg, with a minimum effective dose near 5mg. Individual response varies — start low and adjust.
Timing is flexible for Saccharomyces Boulardii — consistent daily use matters more than the time of day. Saccharomyces boulardii is a non-pathogenic probiotic yeast that colonizes the gut transiently.
Probiotics
Probably helpsLive microorganisms where strain selection determines outcome — Lactobacillus and Bifidobacterium strains best studied for gut, immune, and mood.
L-Glutamine
Likely helpsPrimary fuel for intestinal and immune cells — becomes conditionally essential during stress, illness, or intense training.
Last reviewed May 2026 · evidence from 39 studies · how we score
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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.
Binds to harmful bacteria and removes them
Balances intestinal immune response
Helps maintain intestinal barrier integrity
How Saccharomyces Boulardii works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
250-500mg (5-10 billion CFU) daily
Loading: For acute diarrhea, may use 500mg 2x daily
Can be taken without food
| Form | Type |
|---|---|
| 💊Capsules (lyophilized) | Recommended |
| 🧪Powder | Alternative |
| 💊Sachets | Alternative |
Look for products with verified CFU counts. CNCM I-745 is the most researched strain (Florastor brand).
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.
Based on multiple meta-analyses showing 1.1-1.6 day reduction in diarrhea duration. Effect size appears to plateau at standard therapeutic doses. Limited data on doses above 20 billion CFU.
Prevents antibiotic-associated and traveler's diarrhea
Reduces duration of acute infectious diarrhea
Helps restore healthy gut flora after antibiotics
Avoid; risk of fungemia
Well-studied and safe for pediatric diarrhea
Antifungals will kill S. boulardii - separate by 2+ hours
Tip: Usually transient
Saccharomyces Boulardii is generally well-tolerated and considered safe for most healthy adults at recommended doses. The most commonly reported side effects are gas/bloating. Use caution if any of these apply to you: Central venous catheter (risk of fungemia); Severely immunocompromised; ICU patients.
Colostrum
Mostly mechanism / observationalFirst milk rich in immunoglobulins, growth factors, and antimicrobial compounds that supports gut health, immunity, and recovery.
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