Rankings / Immune & Inflammation
Saccharomyces boulardii
Immune & Inflammation · Probiotic yeast
Tier A
Bottom line
Read Off Label grades Saccharomyces boulardii as A (8.0/10) based on strong evidence, moderate benefit magnitude, and a low-risk safety profile.
Unique advantage of being a yeast — unaffected by concurrent antibiotics.
Studied, labeled, or reported-use context: 250-500 mg 2x/day during and 2 weeks after antibiotic course — OTC; not individualized guidance.
What the evidence says
Unique advantage of being a yeast — unaffected by concurrent antibiotics. One of the most evidence-backed probiotics for specific GI indications. Goldenberg 2017 Cochrane review supports AAD and CDI prevention. Fungemia risk is concentrated in immunocompromised people and those with indwelling central venous catheters.
Mechanism
Non-pathogenic yeast (actually a strain of S. cerevisiae); intrinsically antibiotic-resistant (unlike bacterial probiotics); binds C. difficile toxins A and B; secretes 54 kDa protease that neutralizes toxin A
Studied, labeled, or reported dose & route
250-500 mg 2x/day during and 2 weeks after antibiotic course
This records doses and routes described in studies, approved labeling, clinical practice, or documented use. It is not individualized guidance and does not establish safety; context changes with indication, formulation, health history, monitoring, and other medicines.
Citations
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Common questions
- What does the evidence show about Saccharomyces boulardii's effects?
- Read Off Label rates the evidence for Saccharomyces boulardii as Strong and the benefit magnitude as moderate, producing an overall grade of A (8.0/10). Unique advantage of being a yeast — unaffected by concurrent antibiotics.
- What safety findings are reported for Saccharomyces boulardii?
- Saccharomyces boulardii has a low risk profile in the database. Low (rare fungemia in immunocompromised or central-line patients — FDA warning) Legal status: OTC.
- What doses or routes are reported for Saccharomyces boulardii?
- 250-500 mg 2x/day during and 2 weeks after antibiotic course This is context from studies, approved labeling, clinical practice, or documented use; it is not individualized guidance and does not establish safety.
- How does Saccharomyces boulardii work?
- Non-pathogenic yeast (actually a strain of S. cerevisiae); intrinsically antibiotic-resistant (unlike bacterial probiotics); binds C. difficile toxins A and B; secretes 54 kDa protease that neutralizes toxin A
This is an independent synthesis of published research by a non-clinician. Scores are opinions supported by citations, not prescriptions. See the full disclaimer and methodology for how this score was produced and what it does and doesn't mean.