Common bile duct stones are the most common cause of extrahepatic obstructive jaundice, severe cholangitis, pancreatitis or chronic liver disease and should be treated as soon as possible. Common bile duct stones are divided into primary stones and secondary stones. Primary stones in the common bile duct are bilirubin stones formed by bacterial infection in the bile duct, which are the same as most intrahepatic bile duct stones. Most of the secondary stones in the common bile duct are drained into the common bile duct by gallbladder stones, while some stones are drained into the common bile duct by collapsed intrahepatic bile duct stones. The nature of common bile duct stones originating from the gallbladder is identical to that of stones in the gallbladder. Stones generated in the common bile duct (primary stones) are less common and most of them are secondary stones. The majority of common bile duct stones that develop after gallbladder surgery are the result of stones in the common bile duct that were missed during gallbladder surgery or regenerated stones in the residual small gallbladder that fall into the common bile duct.