The histological changes of the gallbladder and liver following extracorporeal shock wave lithotripsy (ESWL) were investigated in a canine model. After performing ESWL on human cholesterol stones placed in the gallbladder of 8 dogs, the gallbladder and livers were removed for pathological study. The mucosa of the gallbladder showed erosion and ulceration in three of the eight dogs. Edema and bleeding were found in the stroma of the gallbladder beds. Hemorrhagic necrosis and vacuolar degeneration occurred in liver parenchyma adjacent to the gallbladder bed, but the portal area was fairly well preserved. It can be said that ESWL caused damage to both the liver and the gallbladder, but its effects on the liver may be only slight because of the preservation of the portal area.