In diverse parts of the world, many bacterial strains have been recognised as the causative agents of diarrhoea. Great achievements have been made in perceiving the varied mechanisms which explain their intestinal pathogenicity. These achievements include the elucidation of the 5 mechanisms of disease production by Escherichia coli, the mechanisms of action of Shigella, Salmonella, Campylobacter and Yersinia, new information about antimicrobial-associated colitis caused by Clostridium difficile and the recognition of microbes such as Aeromonas hydrophila and Pleisomonas shigelloides. Information is available on the use and indications of antimicrobial treatment in children with diarrhoea of bacterial aetiology which is proven or suspected by clinical symptomatology or simple laboratory procedures. Finally, the usefulness of oral rehydrating solutions has been appreciated in the prevention as well as in the correction of diarrhoeal dehydration.