Aim To review evidence for the effectiveness of Lactobacillus GG (LGG) in treating acute infectious diarrhoea in children.

Methods The following electronic databases were searched through August 2006 for studies relevant to acute infectious diarrhoea and LGG: MEDLINE, EMBASE, CINAHL and The Cochrane Library; additional references were obtained from reviewed articles. Only randomized-controlled trials (RCTs) were included.

Results Eight RCTs (988 participants) met the inclusion criteria. Compared with controls, LGG had no effect on the total stool volume (two RCTs, n = 303). However, LGG was associated with a significant reduction in diarrhoea duration (seven RCTs, 876 infants, weighted mean difference, WMD −1.1 days (95% confidence interval, CI −1.9 to −0.3), particularly of rotavirus etiology (WMD −2.1 days, 95% CI −3.6 to −0.6), risk of diarrhoea >7 days (one RCT, n = 287, relative risk 0.25, 95% CI 0.09–0.75) and duration of hospitalization (three RCTs, n = 535, WMD −0.58, 95% CI −0.8 to −0.4; significance was lost in the random effect model). There was no reduction in the number of stools at any time interval.

Conclusions The use of LGG is associated with moderate clinical benefits in the treatment of acute diarrhoea in children. These findings should be interpreted with caution due to the important methodological limitations and heterogeneity of most of the studies.