The effect of zinc supplementation on intestinal permeability changes and protein loss was studied in 32 children aged between 1 and 12 years during bouts of acute shigellosis and after recovery. An intestinal permeability test and then a 48 hour balance study were performed on all patients. They were then blindly assigned to receive vitamin B syrup either with or without zinc acetate (15 mg/kg per day) for a month. All patients received a five day course of nalidixic acid. The balance study was repeated during convalescence and follow up, but a permeability test was done only at follow up after one month. Intestinal permeability, expressed as a urinary lactulose:mannitol excretion ratio, improved significantly (p = 0.001) along with a significant increase (p = 0.005) in mannitol excretion in the zinc supplemented children, suggesting a resolution of small bowel mucosal damage. The latter was associated with a higher coefficient of nitrogen absorption (p = 0.03), suggesting a possible role of zinc in the treatment of shigellosis. Enteric protein loss, as assessed by faecal alpha 1 antitrypsin clearance, was not influenced by zinc supplementation.