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Bacillus clausii did not shorten diarrhea in one large add-on trial

A trial in young children compared four B. clausii strains with placebo while both groups received oral rehydration and zinc. It did not demonstrate a significant additional benefit for diarrhea duration.

Read the evidence ↓

Supplement Science Insights Editorial Team

Published September 23, 2026

The comparator included the same supportive treatment

The randomized, double-blind study enrolled children aged six months to five years in India. Four B. clausii strains were supplied in a suspension for five days; both groups also received oral rehydration therapy and zinc. [1]

Of 457 randomized children, 454 received treatment. Median recovery times were about 42.8 hours with the probiotic and 42.1 hours with placebo, without a statistically significant difference. Secondary outcomes also did not differ significantly. [1]

Recovery alone does not identify a probiotic effect

Most children recovered in both groups. Their improvement cannot be attributed to the probiotic without a convincing between-group difference, especially when both groups received effective supportive care. [1]

The authors discussed disease severity, timing and sample-size limitations. Several investigators disclosed Sanofi employment or other company relationships. The finding is specific to the tested mixture and setting; it neither proves benefit for all B. clausii products nor removes the need for dehydration assessment. [1]

Compare against the care both groups received

Imagine nearly all children improve during a trial. If recovery is similar with placebo plus standard care, improvement in the probiotic group alone is not evidence of added efficacy.

Evidence summary — Bacillus clausii did not shorten diarrhea in one large add-on trial
DetailInterpretation
Four strainsSpecified mixture
Rehydration and zincGiven to both groups
Added benefitNot demonstrated
Bacillus clausii did not shorten diarrhea in one large add-on trial — original article outline diagram
Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

Sources for this article

  1. Efficacy and safety of Bacillus clausii (O/C, N/R, SIN, T) probiotic combined with oral rehydration therapy (ORT) and zinc in acute diarrhea in children: a randomized, double-blind, placebo-controlled study in India - PubMed
    Source consulted: 2026-09-19. This is a reference resource, not a claim that we conducted the studies or tested a product.