BACKGROUND

Probiotics are microbial cell preparations or components of microbial cells that have a beneficial effect on the health and well being of the host. Probiotics may offer a safe intervention in acute infectious diarrhoea to reduce the duration and severity of the illness.

OBJECTIVES

To assess the effects of probiotics in proven or presumed infectious diarrhoea.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group's trials register (December 2002), the Cochrane Controlled Trials Register (The Cochrane Library Issue 4, 2002), MEDLINE (1966 to 2002), EMBASE (1988 to 2002), and reference lists from studies and reviews. We also contacted organizations and individuals working in the field, and pharmaceutical companies manufacturing probiotic agents.

SELECTION CRITERIA

Randomized controlled trials comparing a specified probiotic agent with placebo or no probiotic in people with acute diarrhoea that is proven or presumed to be caused by an infectious agent.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial methodological quality and extracted data.

MAIN RESULTS

Twenty-three studies met the inclusion criteria with a total of 1917 participants, mainly in countries with low overall mortality rates. Trials varied in relation to the probiotic(s) tested, dosage, methodological quality, and the diarrhoea definitions and outcomes. Probiotics reduced the risk of diarrhoea at 3 days (relative risk 0.66, 95% confidence interval 0.55 to 0.77, random effects model; 15 studies) and the mean duration of diarrhoea by 30.48 hours (95% confidence interval 18.51 to 42.46 hours, random effects model, 12 studies). Subgroup analysis by probiotic(s) tested, rotavirus diarrhoea, national mortality rates, and age of participants did not fully account for the heterogeneity.

REVIEWERS' CONCLUSIONS: Probiotics appear to be a useful adjunct to rehydration therapy in treating acute, infectious diarrhoea in adults and children. More research is needed to inform the use of particular probiotic regimens in specific patient groups.