The effects of Lacticaseibacillus rhamnosus GG supplementation on gastrointestinal and respiratory outcomes: a systematic review and meta-analysis of randomized controlled trials

= 6). Moderate-to-high heterogeneity was observed for the aforementioned outcomes, except GI outcomes other than diarrhea and GI symptom risk. Prediction intervals supported consistent benefits for diarrhea outcomes but frequently crossed the null for others, indicating greater uncertainty. Effects on diarrhea outcomes and respiratory infection risk were more consistent in children; evidence in adults was limited. Certainty was rated moderate for diarrhea outcomes and mostly low for others. LGG supplementation reduces diarrhea risk and duration in children, supported by moderate-certainty evidence and consistent effects across trials. Other outcomes showed more variable results, reflecting limited or inconsistent evidence. These findings support LGG's role in pediatric diarrhea management and prevention while underscoring the need for high-quality trials to clarify broader clinical applications.