Gallbladder function was studied in 22 patients with portal hypertension due to advanced Schistosoma mansoni infection and in 17 healthy adults. The fasting volume of the gallbladder was significantly less in patients than in controls. The gallbladder wall was grossly thickened in the study group. There was a significant difference between the patients and controls in the reduction of gallbladder volume following a fatty meal. Although the portal vein diameter and the splenic volume were significantly larger in study patients, no significant correlation could be detected between the reduction in volume or wall thickness of the gallbladder and any of the relevant sonographic features of schistosomiasis-induced portal hypertension.