Alanine-based oral rehydration therapy for infants with acute diarrhea. Twenty male infants less than 1 year of age with acute diarrhea and dehydration were randomly assigned to a study group and studied in blind fashion in a metabolic unit to assess the efficacy of the addition of 30 mmol/L alanine to the standard World Health Organization (WHO) oral rehydration solution (ORS). Patients were exclusively rehydrated with one of two types of ORS during the first 24 hours of treatment. On the second day, oral feedings were started with a lactose-free formula, and ORS was given to replace stool losses. Body weight, ORS, food intake, vomitus, stool, and urine output were recorded at 6-hour intervals. Blood was drawn at the time of admission, after rehydration, and at 24 and 48 hours of hospitalization to monitor blood gases and electrolytes. Rehydration was satisfactory in both groups of patients. ORS that contained alanine did not reduce the purging rates of the infants compared with those who received standard ORS. Clinically no adverse effect of the alanine-based ORS was observed during hospitalization. None of the patients had significant hypernatremia or hyponatremia, and serum amino acid levels were not altered. These data show that the addition of 30 mmol/L alanine to the standard WHO-ORS produces no further improvement in the outcome of the infants with acute diarrhea compared with those fed the standard WHO-ORS. 