Last verified: 17 days ago
Saccharomyces Boulardii
Also known as: S. boulardii, Saccharomyces cerevisiae var. boulardii, S. boulardii CNCM I-745
Evidence under review. — Not yet rated
Probiotic yeast that reduces diarrhea, supports gut health, and helps prevent C. diff recurrence.
-
What it does
Saccharomyces boulardii is a beneficial yeast used as a probiotic supplement. Clinical trials show it reduces recurrence of Clostridioides difficile infection when added to antibiotic treatment,...
-
Evidence quality
Evidence base hasn't been formally rated yet. See research below.
-
Clinical dose
250-500 mg daily based on study doses
-
Found in
What the Science Says
Saccharomyces boulardii is a beneficial yeast used as a probiotic supplement. Clinical trials show it reduces recurrence of Clostridioides difficile infection when added to antibiotic treatment, and a large real-world registry study found it cuts side effects — including diarrhea, nausea, and abdominal pain — when used alongside H. pylori eradication therapy. It also shows promise for reducing diarrhea in children with acute gastroenteritis, though effects are strain-specific and results vary by condition.
What It Doesn't Do
Not a proven treatment for autism. Won't reliably prevent radiation-induced diarrhea — one trial found mixed and even worse outcomes at certain timepoints. No solid evidence it treats asthma, liver disease, or celiac disease on its own. Not a replacement for antibiotics in serious infections.
Evidence-Based Benefits
Reduces Clostridioides difficile infection recurrence when added to vancomycin treatment.
Moderate EvidenceEffective at: 500 mg every 12 hours for 10 days
Supporting studies (click to view on PubMed):
Reduces nausea, diarrhea, and abdominal pain during H. pylori eradication therapy.
Moderate EvidenceEffective at: No established dose from provided studies
Supporting studies (click to view on PubMed):
Helps shorten diarrhea duration and reduce symptoms in children with acute gastroenteritis.
Moderate EvidenceEffective at: No established dose from provided studies
Supporting studies (click to view on PubMed):
Improves H. pylori eradication success rates when combined with concomitant antibiotic therapy.
Moderate EvidenceEffective at: No established dose from provided studies
Supporting studies (click to view on PubMed):
Absorption & Bioavailability
Unknown — as a yeast-based probiotic, S. boulardii survives gastric transit better than many bacterial probiotics due to its resistance to stomach acid, but formal bioavailability data are not reported in the provided studies.
Red Flags to Watch For
- Immunocompromised individuals face risk of fungemia (yeast entering the bloodstream) — consult a doctor before use
- Results are highly condition-specific; benefits seen in C. diff and H. pylori contexts may not apply to other uses
- One RCT found higher diarrhea incidence at week 4 in the S. boulardii group during pelvic radiotherapy — not universally protective
- Commercial probiotic products vary widely in quality, actual strain content, and regulatory oversight — check for third-party testing
Products Containing Saccharomyces Boulardii
See how Saccharomyces Boulardii is used in these analyzed products:
Frequently Asked Questions
What does Saccharomyces Boulardii do?
Probiotic yeast that reduces diarrhea, supports gut health, and helps prevent C. diff recurrence.
What is the effective dose of Saccharomyces Boulardii?
250-500 mg daily based on study doses
Is Saccharomyces Boulardii safe?
Immunocompromised individuals face risk of fungemia (yeast entering the bloodstream) — consult a doctor before use
What doesn't Saccharomyces Boulardii do?
Not a proven treatment for autism.
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-05-25