Twenty-nine infants and children, age 2-70 months with chronic diarrhea, were admitted to a double-blind, parallel clinical trial. The subjects were randomly assigned to receive either a bismuth subsalicylate liquid or a placebo liquid formulation. Treatment was given for 7 days with dosage varied according to age. Analysis of the results showed that the subjects in the bismuth subsalicylate-treated group gained significantly more weight (p less than 0.05), had significantly fewer (p less than 0.01) and firmer (p less than 0.01) stools with less water content (p less than 0.01) during the course of the study than did the placebo-treated group. Response to treatment, as graded by nursing staff, family, and physicians was moderate to excellent in 86% of the treated group while none of the placebo group received such a rating (p less than 0.01). No differences were noted between stool weights or bile acid excretion.