COOK biliary stent usually refers mainly to the biliary stent manufactured by Cook Medical Devices, Inc. in the U.S. The stent placement needs to be carried out under the guidance of a specialized doctor. The function of biliary stent is mainly to relieve biliary stenosis or release biliary obstruction, so as to control biliary infection and reduce jaundice symptoms. Bile duct stent is mainly used in the treatment of bile duct cancer patients, and the bilirubin of patients with severe jaundice will be significantly reduced after bile duct stenting, and then it is relatively safer to carry out surgical treatment at this time. In addition, for patients with advanced cholangiocarcinoma who can no longer undergo bile duct surgery, biliary stenting can significantly alleviate their clinical symptoms and improve their quality of life.