To evaluate the efficacy of antidiarrheal agents, a study of the treatment on children in Guatemala who had acute diarrheal illness was conducted. Eighty patients, aged 3-11 yr, were hospitalized and treated for 2 days with 1 of 5 agents: kaolin-pectin suspension concentrate (Kao-Con), kaolin suspension, pectin suspension, diphenoxylate-atropine liquid (Lomotil) or placebo. Although the patients receiving kaolin-pectin produced stools that tended to be more formed than those of the placebo-treated group patients, the study did not demonstrate any effect by any of the agents tested in influencing the frequency of bowel movement, the water content of the stools or the weight of stools. Kaolin-pectin suspension and diphenoxylate-atropine liquid do not seem useful in the relief of acute nonspecific diarrhea in children.