150 infants aged under 6 months and admitted to hospital with acute gastroenteritis were treated with rice water (RW), rice-based electrolyte solution (RES), and the glucose electrolyte solution (GES) recommended by the World Health Organisation. Two-thirds of the patients were moderately dehydrated and only 8% had positive stool culture. Vomiting, present in 11%, did not interfere with successful oral rehydration. Before treatment serum electrolytes and other biochemical variables were similar in the three groups. After 48 h of treatment the blood urea nitrogen and serum creatinine were lower (p less than 0.05) in the RW and RES group than in the GES group. Serum potassium was also lower in the RW than in the RES group. RW and RES were superior to GES in reducing the frequency and volume of stool output and in producing weight gain.