Acute acalculous cholecystitis is a well recognized complication of many acute illnesses. Ischaemia of the gallbladder seems to have an important role in its pathogenesis.Microangiography was performed in 15 gallbladders immediately after cholecystectomy by infusing 10 per cent barium sulphate into the specimen. Five patients had symptomatic gallstone disease, five had acute gallstone-associated cholecystitis and five had acalculous cholecystitis. Sections for histological examination were taken from adjacent sides of the microangiography section. Filling of the vessels by contrast medium was compared with histological findings.Microangiography of the gallbladder in acute gallstone-associated cholecystitis showed strongly dilated arterioles and regular filling of the capillary network, whereas in acalculous cholecystitis the capillary filling was poor and irregular.Disturbed microcirculation may play an important role in the pathogenesis of acute acalculous cholecystitis.