The main reasons for cholangitis after cholecystectomy are: easy to appear in the common bile duct sediment-like stones, small stones in the cystic duct are easy to fall off to the common bile duct, the bile in the bile duct is easy to bacterial infection and so on. 1. Prone to choledochal sediment-like stones: patients often have choledochal sediment-like stones before cholecystectomy, and the stones in the choledochal duct are easy to stimulate the mucous membrane of the bile duct after the operation, resulting in cholangitis. 2. Small stones in the common bile duct are easy to be dislodged to the common bile duct: because of the existence of small stones in the cystic duct, they are easy to be dislodged to the common bile duct to cause obstruction, and then irritate the mucous membrane of the bile duct and cause cholangitis. 3. Bile in the bile duct is easy to be infected by bacteria: if the gallbladder is seriously infected, cholecystectomy is not aseptic surgery and bacteria are easy to exist in the gallbladder, so bacteria enter the bile in the bile duct during surgery and cause infection, resulting in cholangitis. Cholangitis is a common complication of cholecystectomy and should be treated as soon as it is diagnosed.