Asymptomatic extrahepatic bile duct stones that do not empty into the intestine on their own need prompt treatment, otherwise they can cause biliary obstruction and lead to serious biliary infections. Extrahepatic bile duct stones include primary stones and secondary stones, which are caused by biliary infection, biliary obstruction, and segmental dilatation of the bile duct. Extrahepatic bile duct stones are usually asymptomatic or only have upper abdominal discomfort, and can be left untreated if the stones are small enough to enter the intestines on their own. However, some stones are slightly larger in size and may cause obstruction of the bile ducts, resulting in inflammation of the bile ducts, or in severe cases, life-threatening acute pyogenic cholangitis. Surgery is usually recommended to remove such stones in time to avoid more serious manifestations.