An evaluation of the oral intake and the need for alternative therapy in aboriginal and white (European ancestry) children hospitalized for dehydration due to diarrhoea revealed significant differences in drinking behaviour. In a retrospective study of 120 children (36 aboriginal), the white children were far more likely to require an alternative mode of fluid administration (39 of 86 white versus 3 of 34 aboriginal). In a prospective study, although treated in the same manner by the same staff, during the first eight hours after admission white children had a mean oral intake of 2.9 ml/kg/hr (range 0.4-6.6, S.D. 1.6) whereas the aboriginal children had a mean oral intake of 6.1 ml/kg/hr (range 2.2-9.2, S.D. 2.1). The drinking behaviour of children varies with racial and/or cultural background. This should be considered in designing and administering rehydration solutions.