PIP: This report describes the authors' experiences among Apache Indians who required rehydration therapy because of acute diarrhea. About 400 children, aged less than 2 years, who were strong enough to drink, were given oral glucose-electrolyte solutions. The solution contained, in millimoles per liter, sodium (81), potassium (18), chloride (71), bicarbonate (28), and glucost (139). The cost of the formula is 2.5 cents per liter. In children with a 2 degree volume depletion, more of the solution was required (statistically significant) than if the child suffered 1 degree volume depletion; however, 9 of 11 children with 2 degree depletion were adequately hydrated 3-6 hours after administration. Moderate electrolyte abnormalities, which included hypo- and hypernatremia and acidosis, were corrected or improved during the administration of the oral rehydration therapy. Plasma potassium concentrations showed little change. The oral therapy failed in 2 children due to malabsorbed glucose, but both were successfully treated with intravenous fluids, a carbohydrate-free formula, and broad-spectrum antibiotics. The ad libitum sue of oral therapy is effective and should help reduce infant mortality and morbidity due to diarrhea.