 Rarely, consumption of probiotics may cause bacteremia, fungemia and sepsis, potentially fatal infections, in children with lowered immune systems or who are already critically ill.

One of the better documented effects of "L. reuteri" is in the treatment of diarrheal diseases in children, where it significantly decreases symptom duration.Treatment of rotaviral diarrhea with "L. reuteri" significantly shortens the duration of the illness as compared to placebo.This effect is dose-dependent