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Sb9.0
Saccharomyces Boulardii Research
Likely helpsHigh safety
27 peer-reviewed studies
What the evidence says
Likely helps
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
High
What the studies found
12helped2didn't help· 13 more without graded effect data
By outcome
Digestive health & diarrheaProbiotic yeast prevents and treats diarrhea, restores gut flora · 1-2 weeks
Likely helps24 studies
Safety profile
Probably helps9 studies
Therapeutic & clinical
Too few graded studies2 studies
InflammationPrevention and treatment of diarrhea, gut protection · Days to 1 week
Too few graded studies1 study
By the numbers
Pulled from 26 studies with measurable effects
Likely real effects
78%
across studies
People studied
53k
typical study: 156 people
Strongest designs
22
14 pooled, 8 randomised
Showed benefit
86%
12/14 studies
How long studies ran
1–4 weeks
2
1–3 months
1
3+ months
1
Populations Studied
Patients with H. pylori infection4
Patients with Helicobacter pylori infection3
Travelers3
Patients with gut pathogenic bacteria1
Active research area
15 studies in the last 5 years · Latest meta-analysis: 2025
200520152025
1H. pylori eradication rateMeta-AnalysisCited 9×n=5,036 · very large study2025
S. boulardii supplementation in traditional eradication therapy significantly improves the H. pylori eradication rate and reduces the total adverse effects and incidence of diarrhea, bloating, constipation, and nausea.
Li M et al. · Frontiers in cellular and infection microbiology (2025)
S. boulardii supplementation in traditional eradication therapy significantly improves the H. pylori eradication rate and reduces the total adverse effects and incidence of diarrhea, bloating, constipation, and nausea.
2Pathogenic bacteria decolonizationMeta-AnalysisCited 40×n=2,871 · very large study2024
Protocol registration: PROSPERO (ID = CRD42021276045).
Rahman MN et al. · Gut microbes (2024)
Large benefit
← WorseNo effectBetter →
Likely real
This review aims to analyze available evidence from human-controlled trials to determine the effect size of probiotic interventions in decolonizing AMR pathogenic bacteria from the gut.
The persistence of pathogenic bacteria after treatment was 22%(probiotics) and 30.8%(placebo).
The pooled odds ratio was 0.59(95% CI:0.43-0.81), favoring probiotics with moderate certainty (p = 0.0001) and low heterogeneity (I2 = 49.2%, p = 0.0001).
3Acute infectious diarrhoea durationMeta-AnalysisCited 110×n=12,127 · very large study2020
Probiotics probably make little or no difference to the number of people who have diarrhoea lasting 48 hours or longer, and we are uncertain whether probiotics reduce the duration of diarrhoea.
Collinson S et al. · The Cochrane database of systematic reviews (2020)
Effect size was similar in the sensitivity analysis and marked heterogeneity persisted.
Effect size was similar and marked heterogeneity persisted in pre-specified subgroup analyses of the primary outcomes that included all studies.
In six trials (433 participants) of Lactobacillus reuteri, there was consistency amongst findings (I² = 0%), but risk of bias was present in all included studies.
4H. pylori eradication ratesMeta-AnalysisCited 56×n=3,592 · very large study2019
Our meta-analysis shows that S boulardii supplementation on standard eradication therapy significantly increased H pylori eradication rates and reduced the incidence of total side effects and some gastrointestinal adverse effects during eradication therapy.
Zhou BG et al. · Helicobacter (2019)
In addition, the need for discontinuation rate in S boulardii supplementation group was significantly lower than in the control group (RR = 0.33, 95%CI:0.16-0.69, P = .003; moderate quality evidence).
Our meta-analysis shows that S boulardii supplementation on standard eradication therapy significantly increased H pylori eradication rates and reduced the incidence of total side effects and some gastrointestinal adverse effects during eradication therapy.
The addition of S. boulardii to bismuth quadruple therapy significantly increased H. pylori eradication rates and decreased the adverse effects.
Jiang YZ et al. · BMC gastroenterology (2025)
Barely noticeable harm
← WorseNo effectBetter →
Notably, S. boulardii supplementation to bismuth quadruple therapy significantly improved H. pylori eradication rates (RR = 1.08, 95% CI: 1.04-1.12) and reduced the incidence of total adverse effects (RR = 0.53, 95% CI: 0.45-0.62).
We recommend adding 500 mg/day S. boulardii concurrently with bismuth quadruple therapy and continuing this therapy for > 10 days for optimal H. pylori eradication efficacy.
Adding probiotics, particularly S. boulardii or multi-strain combinations, to BQT significantly improves eradication efficacy and decreases treatment-related adverse events.
Liu YH et al. · International journal of antimicrobial agents (2025)
Large harm
← WorseNo effectBetter →
Likely real
PBQT significantly improved H. pylori eradication rates compared to BQT alone (pooled odds ratio [OR] = 1.49, 95% confidence interval [CI] 1.20-1.85; P = 0.0004), with low heterogeneity (I² = 0%).
Subgroup analyses demonstrated that both Saccharomyces boulardii (OR = 1.62; P < 0.05) and multi-strain probiotics (OR = 1.66; P < 0.05) significantly enhanced eradication rates.
Concomitant administration of probiotics with antibiotics also yielded significant benefits (OR = 1.48, 95% CI 1.14-1.92; P = 0.003).
12Probiotic efficacy across conditionsSystematic ReviewCited 162×2018
The choice of an appropriate probiotic is multi-factored, based on the mode and type of disease indication and the specific efficacy of probiotic strain(s), as well as product quality and formulation.
Sniffen JC et al. · PloS one (2018)
Of the 22 types of probiotics reviewed, 15 (68%) had strong-moderate evidence for efficacy for at least one type of disease.
The choice of an appropriate probiotic is multi-factored, based on the mode and type of disease indication and the specific efficacy of probiotic strain(s), as well as product quality and formulation.
14Mucositis incidence and symptom improvementSystematic ReviewCited 33×n=15 · very small study2019
Our analysis suggests that a combination of Bifidobacterium longum, Lactobacillus acidophilus, Bifidobacterium breve, Bifidobacterium infantis, and Saccharomyces boulardii could be a good combination of probiotics to reduce incident rates of mucositis or ameliorate its symptoms in chemo or radiotherapy treated patients.
Picó-Monllor JA et al. · Nutrients (2019)
After applying our inclusion and exclusion criteria, 15 studies were accepted for review and critical analysis.
15Prevention of antibiotic-associated diarrheaMeta-AnalysisCited 334×n=31 · small study2010
The use of S. boulardii as a therapeutic probiotic is evidence-based for both efficacy and safety for several types of diarrhea.
McFarland LV · World journal of gastroenterology (2010)
Huge benefit
← WorseNo effectBetter →
Likely real
Of 31 randomized, placebo-controlled treatment arms in 27 trials (encompassing 5029 study patients), S. boulardii was found to be significantly efficacious and safe in 84% of those treatment arms.
A meta-analysis found a significant therapeutic efficacy for S. boulardii in the prevention of antibiotic-associated diarrhea (AAD) (RR = 0.47, 95% CI: 0.35-0.63, P < 0.001).
In adults, S. boulardii can be strongly recommended for the prevention of AAD and the traveler's diarrhea.
17Prevention of Clostridium difficile infection relapseSystematic ReviewCited 51×2009
S boulardii seems to be well tolerated and may be effective for secondary prevention in some specific patient populations with particular concurrent antibiotic treatment.
Tung JM et al. · Canadian journal of gastroenterology = Journal canadien de gastroenterologie (2009)
Large benefit
← WorseNo effectBetter →
Borderline
One trial showed a reduction of relapses in patients experiencing recurrent CDI (RR=0.53; P<0.05).
The other demonstrated a trend toward reduction of CDI relapse in the recurrent treatment group of patients receiving high-dose vancomycin (RR=0.33; P=0.05).
These studies lacked the power to detect statistically significant differences.
19Helicobacter pylori eradication and adverse effectsRCTCited 19×n=156 · medium study2022
S. boulardii could significantly reduce some AEs of H. pylori eradication therapy, but effectiveness of Lactobacillus reuteri on these cases was not significant.
Naghibzadeh N et al. · BMC gastroenterology (2022)
S. boulardii could significantly reduce some AEs of H. pylori eradication therapy, but effectiveness of Lactobacillus reuteri on these cases was not significant.
It is recommended to conduct the future research with larger sample size in order to investigate the effect.
20Helicobacter pylori eradication ratesRCTCited 2×n=126 · medium study2024
Addition of S. boulardii to VA-dual for 10 days is as effective as the 14-days bismuth-based quadruple regimen while ensuring fewer adverse events and lesser cost.
Yu J et al. · BMC gastroenterology (2024)
Huge benefit
← WorseNo effectBetter →
Could be chance
The H. pylori eradication rates of VAS and ECAB groups by intention-to-treat analysis were 87.3% and 88.9% (P = 1.000) and by per-protocol analysis were 87.3% and 91.8% (P = 0.560), respectively.
Addition of S. boulardii to VA-dual for 10 days is as effective as the 14-days bismuth-based quadruple regimen while ensuring fewer adverse events and lesser cost.
This regimen is particularly suitable for low-BSA patients or non-smokers.