On the grounds of 98 own clinico-pathomorphologic studies and analysis of 112 records the authors have come to the conclusion that at the root of the pathogenesis of acute cholecystitis in elderly and senile patients is the disorder of the gall-bladder wall blood supply, resulting from thrombosis of atherosclerotic vessels against the back-ground of increased coagulation. The authors believe, that the treatment of cholecystitis in these patients with drugs, decreasing the coagulation of the blood and improving hemocirculation, has pathogenetic grounds.