Across 11 studies, 8 reported beneficial effects of Saccharomyces boulardii on reducing diarrhea rates, with effect sizes ranging from small to large (predominantly small to moderate). The most-studied populations are children with acute gastroenteritis or Helicobacter pylori infection, and a common dose was 250 mg once or twice daily. Median study duration was 33 days (across 2 studies that reported it), though durations varied widely.
Caveats: Available evidence is overwhelmingly positive (8 of 11 studies beneficial, 8 statistically significant) — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Three smaller RCTs found neutral effects, particularly in hospitalized patients and those with radiotherapy-induced diarrhea, suggesting benefit may be context-dependent. Several studies lacked dose or duration details, and the evidence base includes meta-analyses with variable quality ratings (low to moderate).
abdominal distention (RR = 0.39, 95% CI: 0.26-0.59)
from: Effect of Saccharomyces boulardii supplementation to bismuth quadruple therapy on Helicobaconstipation (RR = 0.32, 95% CI: 0.18-0.55)
from: Effect of Saccharomyces boulardii supplementation to bismuth quadruple therapy on HelicobaSpecifically, it reduced the incidence of some gastrointestinal adverse effects and nonspecific adverse effects, including diarrhea (RR = 0.28, 95% CI: 0.22-0.36)
from: Effect of Saccharomyces boulardii supplementation to bismuth quadruple therapy on Helicobathe treatment group experienced a significantly higher incidence of diarrhea at week 4 compared to the control group (p=0.03)
from: Impact of Saccharomyces boulardii on acute gastrointestinal toxicities in patients undergonausea (RR = 0.59, 95% CI: 0.36-0.97)
from: Effect of Saccharomyces boulardii supplementation to bismuth quadruple therapy on Helicobarash (RR = 0.49, 95% CI: 0.28-0.86)
from: Effect of Saccharomyces boulardii supplementation to bismuth quadruple therapy on Helicobano significant differences were found between the groups in terms of ... anti-diarrheal medication use
from: Impact of Saccharomyces boulardii on acute gastrointestinal toxicities in patients undergoOverall, no significant differences were found between the groups in terms of cumulative GI toxicities
from: Impact of Saccharomyces boulardii on acute gastrointestinal toxicities in patients undergoThere was no report of any adverse events.
from: Efficacy and Safety of Saccharomyces boulardii in Acute Rotavirus Diarrhea: Double Blind RThere were no adverse drug reactions in both groups.
from: Effectiveness and Safety of Saccharomyces Boulardii for the Treatment of Acute Gastroenterthis review and meta-analysis show that S. boulardii is safe
from: Efficacy and Safety of Saccharomyces boulardii for Acute DiarrheaThe drug was well accepted and tolerated. There were no reports of the side effects during treatment period.
from: Role of a probiotic (Saccharomyces boulardii) in management and prevention of diarrhoea.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).
from: Effect of Saccharomyces boulardii supplementation to bismuth quadruple therapy on HelicobaThere were no discernable adverse effects of yeast administration.
from: Prevention of antibiotic-associated diarrhea by Saccharomyces boulardii: a prospective stuNone of the trials evaluated the effect of S boulardii on stool volume.
from: Systematic review with meta-analysis: Saccharomyces boulardii for treating acute gastroentAdverse effects were epigastric burning and constipation in M (53%) and M+SB (36%), and flatulence/diarrhea in SB (22%).
from: Effectiveness of Saccharomyces boulardii and Metronidazole for Small Intestinal BacterialS boulardii reduced the risk of diarrhoea on day 2 to day 7 (low quality of evidence).
diarrhea (n = 13 RCTs, 14.7% vs. 32.4%, RR = 0.46, 95% CI: 0.37-0.56, P < 0.00001)
Overall, no significant differences were found between the groups in terms of ... anti-diarrheal medication use
In the following two months, S. boulardii group had a significantly lower frequency of 0.54 episodes as compared to 1.08 episodes in control group.
Of C. difficile-positive patients, 31% (5/16) on placebo developed diarrhea compared with 9.4% (3/32) on S. boulardii; this difference was not statistically significant (p = 0.07).
day 4 (RR, 0.38; 95% CI, 0.24 to 0.59) after intervention compared with control
diarrhea (RR = 0.28, 95% CI: 0.22-0.36)
treatment with Saccharomyces boulardii reduced the average number of diarrhea after 3 days of treatment by about 1.03 (MD = -1.03, 95% CI: -1.53, -0.53)
and persistence of diarrhea lasting beyond day 7
The mean duration of diarrhoea was 6.16 days (range 2-13 days) in the placebo group and 4.70 days (range 2-10 days) in the S. boulardii group (p<0.05).
The SB and M + SB groups had decreased diarrhea, abdominal pain, and gas/bloating/flatulence, but M remained unchanged.