PIP: The authors conducted a double blind trial to determine how accurately the mothers made up the feeds provided them during the winter of 1976-77 as oral treatment for acute gastroenteritis. Parents of 73 children under 18 months of age who were suffering from acute gastroenteritis were given either sucrose (39) or glucose (34) to add to a carbohydrate electrolyte mixture. Of 36 mothers selected at random and asked how they made up the solutions, only 2 mothers appeared to sterilize or make up the feeds inadequately. The ranges of osmolality and electrolyte composition were wide: 145 to 360 mosmol/kg for the sucrose solution, and 192 to 600 for the glucose solutions. Correct osmolalities were 216 and 315 respectively. There was no correlation observed between variability and need for admission. Variance of osmolality was significantly greater in those who were admitted in the glucose-treated group (32%; p or = 0.01, F test), but not in the sucrose-treated group, suggesting that the risk of producing hyperosmolar feeds is greater when glucose solutions are incorrectly made up. Both groups had the same recovery time (2-6 days, mean 3.6) where outpatient treatment was successful. The data confirm the previous observation that sucrose was at least as effective as glucose. The authors now provide diluted electrolyte mixture to which parents only add sucrose. Sucrose mixture is effective, of low osmotic load, and is also relatively cheap. Its use in outpatient treatment of infantile acute gastroenteritis is recommended.