Study Design: It will be a phase IV surveillance study of adverse effects, particularly symptomatic hyponatraemia associated with routine use of hypo-osmolar ORS solution in the treatment of diarrhoea patients of all ages and of any aetiology in a hospital that admits a large number of diarrhoea patients. Hypo-osmolar ORS as recommended by WHO is now being routinely used for all patients admitted to a hospital which admits a large number of diarrhoea patients including cholera. The hospital serves a metropolitan city and it’s suburbs known to be endemic for cholera.