Acute community-acquired diarrhoea is a major cause of mortality in developing countries. Current treatment is limited to oral rehydration treatment (ORT). However, ORT fails to decrease diarrhoea duration and stool volume and hence active treatment in conjunction with probiotics is recommended for the management of community-acquired diarrhoea. This study is the first large-scale study in Latin America demonstrating the efficacy, acceptability and safety of B. clausii in the treatment of children with acute community-acquired diarrhoea.