Lactobacillus rhamnosus and Improved Gastrointestinal Symptoms

Across 3 studies, all reported beneficial effects of Lactobacillus rhamnosus on gastrointestinal symptoms, with effect sizes ranging from small to moderate. The largest study (a systematic review in an autism spectrum disorder population, n=1769) showed a small beneficial effect, while two smaller studies (including a clinical trial in an oncological cohort) showed moderate effects. Evidence is preliminary and limited by the small number of studies and lack of statistically significant findings.

• Studied populations: autism spectrum disorder (ASD), oncological patients undergoing treatment

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. None of the included studies reported statistically significant findings, suggesting the observed beneficial effects may be smaller or less reliable than the direction implies. Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Dosing and form were not consistently reported, limiting applicability.