ABSTRACT. Two groups of infants aged 2 to 20 months with moderate to severe dehydration were randomly assigned to either sucrose high sodium (90 mEq/l) or sucrose low sodium (58 mEq/l) solution in a double blind manner. Rehydration was assessed on clinical grounds and confirmed by serial determination of body weight, hematocrit, total serum protein and blood urea nitrogen. Twenty (80%) of 25 patients on sucrose high sodium solution and 20 (77%) of 26 patients on sucrose low sodium solution were successfully hydrated. Only the assigned sucrose-electrolyte solution was given during the average rehydration period of about 7 hours when the serum electrolytes were remeasured. Three patients on high sodium solution developed mild hypernatremia. Slight hyponatremia was encountered in 2 patients on low sodium solution. Purging rate was significantly higher in patients who failed as compared to those who succeeded. The results of this study suggest that oral sugar electrolyte solution with sodium concentration of 90 mEq/l is safe and effective in the majority of infants with diarrhoeal dehydration of diverse causes. However, intravenous fluids must be available particularly for those with a high purging rate as a significant number of them may fail.