Infectious gastroenteritis continues to be a leading cause of mortality and morbidity worldwide and, while rotavirus vaccination will certainly reduce the incidence, it is unlikely to make a significant impact on this condition. The cornerstone of treatment remains replacement of water and electrolyte losses with oral rehydration solution (ORS). In areas with low vitamin A status, supplementation of the latter may be of benefit and, in time, the addition of zinc may become routine. A few years ago, probiotics were discussed primarily in the context of alternative medicine. Probiotics are now entering mainstream medical practice since they have been shown to decrease the severity and shorten the duration of infectious gastroenteritis by approximately 24 hours and are therefore a potent add-on therapy. Curtailing the duration of diarrhoea as well as reducing hospital stays, emphasises the social and economic benefits of probiotic treatment in adjunction to ORS in acute infectious gastroenteritis in children. Evidence in viral gastroenteritis is more convincing than in bacterial or parasitic infection. Mechanisms of action are strain specific, and only those probiotic strains for which there is evidence of clinical efficacy should be recommended. In acute gastroenteritis, there is evidence of efficacy of some strains of lactobacilli ( Lactobacillus caseii GG and L. reuteri ) and Saccharomyces boulardii. Although probiotics are ‘generally regarded as safe’, side-effects such as septicaemia have very rarely been reported.