The effects of cow's milk and a soy-based formula without disaccharides on the recovery rates of hospitalized infants with acute diarrhea were compared. Thirty-five infants constituted the milk-treated group and 40 infants formed the soy-formula group. Significant differences were found in duration of diarrhea (3.48±0.23 vs. 6.28±0.67 days, p<0.001), number of days requiring intravenous fluids (4.65±0.24 vs. 6.8±0.88, p<0.01) and length of hospital stay (10.5±0.73 vs. 12.8±1.65 days, p<0.04), favoring the soy-based formula. These results can be related to the known transient deficiency in intestinal lactase during acute diarrhea; however, differences in components other than carbohydrates (i.e. protein) could play a role as well.