Saccharomyces boulardii
Commonly used for
NutritionDiarrheaBloating
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What is it? / Overview
Unlike bacterial probiotics S. boulardii is a beneficial yeast not killed by antibiotics. It has strong evidence for reducing antibiotic-associated diarrhea and may help reduce recurrence of C. difficile infection alongside standard treatment.
How is it used? / Administration
Form: S. boulardii CNCM I-745 (clinically studied strain)
Typical dose studied: 250–500 mg/day (~5–10 billion CFU/day)
Timing: With or without food; separate from antibiotics by at least 2 hours
Choose CNCM I-745 strain when possible. Never combine with antifungal medications.
How well does it work? / Evidence
✓ Well-established
Who should avoid it?
Avoid with: Organ transplant (on immunosuppression)
Interacts with: Oral antifungal medications — reduce effectiveness
Already taking it? Continue only while clinically indicated during and shortly after antibiotic therapy. Central venous catheters are a genuine, documented S. boulardii fungemia risk factor (case reports of catheter-related fungemia exist) -- worth flagging to a doctor if one is in place.
Research & references
McFarland LV. (2010). S. boulardii in adult patients systematic review. World Journal of Gastroenterology. Goldenberg JZ et al. (2017). Probiotics for C. difficile prevention. Cochrane Database. Czerucka D et al. (2007). Yeast as probiotics review. Alimentary Pharmacology & Therapeutics.
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