Diarrhoea continues to have a devastating impact in infants and children. It is a major cause of retarded growth. Substantial declines in hospitalization rates and possibly in the mortality due to diarrhoea have occurred following the launch of programmes based on oral rehydration therapy, and yet about 1 million diarrhoea-related deaths occur each year in South-East Asia. The World Health Organization currently recommends oral rehydration therapy plus continued breast- and complementary feeding for children with diarrhoea, and antibiotics for dysentery or associated systemic infection. Although oral rehydration therapy has achieved substantial acceptance, physicians and families continue to prescribe and seek drug therapy to reduce diarrhoeal duration and severity. Research is aimed at developing improved oral rehydration salt solutions or identifying adjunct therapy that will provide substantial benefit in reducing stool output together with safety and selectivity of action. It must, however, be recognized that control of malnutrition is a key requirement to reduce the duration and severity of acute diarrhoea.