tuneTypical Dose
250-500 mg daily (5-10 billion CFU) for AAD prevention. 250-750 mg daily for acute diarrhea treatment.
Microbiome Modulator
Saccharomyces boulardii
Saccharomyces boulardii CNCM I-745
Evidence TierBWADA NOT PROHIBITED
watchEffect Window
S. boulardii reaches steady-state gut levels within 3 days of starting. Cleared from the GI tract within 3-5 days of stopping.
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Saccharomyces boulardii is a probiotic yeast with strong meta-analytic evidence for preventing antibiotic-associated diarrhea and reducing the duration of acute diarrhea in children.
S. boulardii is one of the best-supported probiotics for a specific clinical job. Meta-analyses show it can meaningfully reduce antibiotic-associated diarrhea risk and shorten pediatric acute-diarrhea courses. Newer supportive studies still fit those GI lanes rather than turning S. boulardii into a universal microbiome fix. Safety is excellent in immunocompetent individuals, but fungemia risk in critically ill, immunocompromised, or centrally catheterized patients is real and well-documented.
S. boulardii is a probiotic yeast that produces a serine protease degrading C. difficile toxins, stimulates secretory IgA, modulates NF-kB-driven inflammation, enhances brush border enzyme expression, and survives antibacterial antibiotics because it is a yeast rather than a bacterium.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Reduces antibiotic-associated diarrhea risk by approximately half (RR 0.47, NNT 10) in both adults and children
Secondary Outcomes
- Reduces acute diarrhea duration in children by approximately 20 hours
- Reduces hospital stay in children with acute gastroenteritis by approximately 1 day
- Well tolerated in immunocompetent individuals with a safety profile similar to placebo
Safety
Contraindications and Interactions
Contraindications
- Critically ill or ICU patients
- Immunocompromised individuals
- Central venous catheter
- Severe acute pancreatitis
Side effects
- Gas or bloating
- Constipation
Interactions
- Antifungal medications (fluconazole, itraconazole, etc.)
- Antibacterial antibiotics
Avoid if
- Critically ill, in ICU, or immunocompromised
- Central venous catheter is in place
- Currently on systemic antifungal medication
Evidence
Study-level References
sb-SRC-001Systematic review and meta-analysis of randomized controlled trials
Sourceopen_in_newSzajewska H, Kołodziej M. Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea. Aliment Pharmacol Ther. 2015;42(7):793-801.
Population: Children and adults receiving antibiotics from 21 RCTs (n=4,780)
Dose protocol: S. boulardii vs placebo or no treatment for AAD prevention across 21 RCTs (n=4,780).
Key findings: RR 0.47 (95% CI 0.38-0.57) for AAD. NNT 10. Consistent in children (RR 0.43) and adults (RR 0.49).
Notes: The definitive meta-analysis for S. boulardii and AAD prevention. Large pooled sample, consistent direction, and clinically meaningful NNT.
Paper content
Landmark meta-analysis confirming that S. boulardii reduces antibiotic-associated diarrhea risk by approximately half compared with placebo or no treatment. The effect was consistent in both children (RR 0.43) and adults (RR 0.49). The NNT of 10 means that for every 10 patients given S. boulardii alongside antibiotics, one case of antibiotic-associated diarrhea is prevented. This is the most comprehensive pooled analysis for this specific indication.
sb-SRC-002Systematic review and meta-analysis of randomized controlled trials
Sourceopen_in_newFeizizadeh S, Salehi-Abargouei A, Akbari V. Efficacy and safety of Saccharomyces boulardii for acute diarrhea. Pediatrics. 2014;134(1):e176-91.
Population: Children with acute diarrhea from 22 RCTs
Dose protocol: S. boulardii vs placebo or standard care for acute diarrhea in children across 22 RCTs.
Key findings: Diarrhea duration reduced by approximately 20 hours (95% CI -26 to -13 hours). Stool frequency reduced on days 2 and 3.
Notes: Comprehensive meta-analysis confirming efficacy for pediatric acute diarrhea. Published in Pediatrics, a high-quality journal for this population.
Paper content
Meta-analysis of 22 RCTs demonstrated that S. boulardii significantly reduced diarrhea duration by approximately 20 hours in children with acute diarrhea. It also reduced stool frequency on days 2 and 3 and lowered the risk of diarrhea persisting on days 3 and 4. The authors concluded that S. boulardii is safe and has clear beneficial effects in children with acute diarrhea.
sb-SRC-003Systematic review and meta-analysis of randomized controlled trials
Sourceopen_in_newFu H, Li J, Xu X, Xia C, Pan Y. Effectiveness and Safety of Saccharomyces Boulardii for the Treatment of Acute Gastroenteritis in the Pediatric Population. Comput Math Methods Med. 2022;2022:6234858.
Population: Children with acute gastroenteritis from 10 RCTs (n=1,282)
Dose protocol: S. boulardii vs standard care or placebo for pediatric acute gastroenteritis across 10 RCTs (n=1,282).
Key findings: Confirmed ~20 hour diarrhea duration reduction and ~1 day shorter hospital stay. No adverse drug reactions reported.
Notes: More recent confirmation of the pediatric acute diarrhea findings with additional hospital stay endpoint.
Paper content
Meta-analysis of 10 RCTs with 1,282 children confirmed that S. boulardii significantly reduces diarrhea duration (by ~20 hours), hospital stay (by ~1 day), and the risk of continued diarrhea after treatment. No adverse drug reactions were reported across included trials.
sb-SRC-004Prospective comparative study.
Sourceopen_in_newMaev IV, Andreev DN, Shaburov RI, et al. Study on the efficacy of combination therapy with rifaximin and Saccharomyces boulardii CNCM I-745 in patients with small intestinal bacterial overgrowth associated with long-term use of proton pump inhibitors. Ter Arkh. 2025;97(8). doi:10.26442/00403660.2025.08.203301. PMID:40884341.
Population: Adults with small intestinal bacterial overgrowth (SIBO) associated with long-term proton pump inhibitor use.
Dose protocol: S. boulardii CNCM I-745 plus rifaximin vs rifaximin alone in 108 patients with PPI-associated SIBO.
Key findings: Combination therapy showed lower SIBO persistence and better symptom resolution than rifaximin alone.
Notes: Non-randomized prospective design limits causal conclusions. Extends S. boulardii evidence into GI dysbiosis beyond AAD.
Paper content
This prospective comparative study examined whether adding S. boulardii CNCM I-745 to rifaximin improves outcomes in 108 patients with SIBO linked to chronic PPI use. The combination arm showed lower SIBO persistence rates and better symptom resolution compared to rifaximin alone. The study extends S. boulardii evidence beyond its primary AAD prevention indication into a GI dysbiosis context. While the non-randomized design limits causal inference, the findings are consistent with the yeast probiotic's known gut-stabilizing mechanisms and support its potential value as an adjunct in PPI-associated SIBO management.
sb-SRC-005Meta-analysis of randomized controlled trials.
Sourceopen_in_newMa F, Huang H, Tian K, Wang W. Efficacy and safety of Saccharomyces boulardii with standard quadruple therapy for eradication of Helicobacter pylori in adults: meta-analysis. J Coll Physicians Surg Pak. 2025;35(11):1440. doi:10.29271/jcpsp.2025.11.1440. PMID:41247686.
Population: Adults with Helicobacter pylori infection across 11 RCTs (n=2,295).
Dose protocol: Meta-analysis of 11 RCTs (n=2,295) evaluating S. boulardii adjunct to bismuth quadruple therapy for H. pylori.
Key findings: Higher H. pylori eradication rates (78.6-89.2%) and reduced diarrhea and rash with S. boulardii adjunct.
Notes: Extends S. boulardii role beyond AAD into H. pylori eradication support. Large pooled sample.
Paper content
This 2025 meta-analysis usefully modernizes Saccharomyces boulardii by extending it into H. pylori support rather than trying to relabel it as a general microbiome fix. Across 11 RCTs and 2,295 adults, adjunctive S. boulardii improved eradication rates and reduced treatment-related diarrhea and rash when added to quadruple therapy. The pooled signal is practical and clinically relevant, but it should be interpreted as adjunctive evidence around a specific antimicrobial regimen, not as proof of broad standalone GI efficacy.
sb-SRC-006Multicenter retrospective comparative effectiveness study
Sourceopen_in_newLiu Q, Liu L, Zhou J, Duan Y, Shi C, Zeng Y, et al. Saccharomyces boulardii and Bifidobacterium co-treatment for antibiotic associated diarrhea in pediatrics: a multicenter efficacy and safety study. Front Cell Infect Microbiol. 2025;15:1575605. doi:10.3389/fcimb.2025.1575605. PMID:40630636.
Population: Infants and young children receiving antibiotics in Chinese clinical settings.
Dose protocol: 10 billion CFU daily during antibiotic treatment and for 7 days afterward in children.
Key findings: Multicenter pediatric comparative study favored Saccharomyces boulardii on diarrhea-timing outcomes versus comparator strategies.
Notes: Observational design means it should support, not replace, the older randomized antibiotic-associated-diarrhea literature.
Paper content
This pediatric study is not randomized, so it does not replace the classic antibiotic-associated-diarrhea meta-analyses. It is still useful because it reflects modern real-world prophylaxis patterns and supports the practical role of Saccharomyces boulardii during antibiotic courses in children.