Endoscopic retrograde cholangiopancreatography, a new examination technique developed in the 1970s, has expanded the examination methods for bile duct and pancreatic duct diseases. In recent years, transendoscopic papillotomy, common bile duct lithotomy and bile duct drainage have been carried out on this basis to relieve obstructive factors and avoid the pain of open surgery. ERCP indications It is generally considered that all suspected pancreaticobiliary diseases are indications, mainly including: 1, suspected bile duct stones, tumors, inflammation, parasites or obstructive jaundice with unknown causes. 2. Recurrence of symptoms after cholecystectomy or bile duct surgery. 3, clinical suspicion of pancreatic tumor, chronic pancreatitis or recurrent pancreatitis in remission. 4.Suspected inflammation or tumor of the duodenal papilla or jugular abdomen, and biliary pancreatitis to remove the cause. 5.Suspected congenital malformation such as common bile duct cyst and pancreaticobiliary duct confluence abnormalities. 6.Unexplained epigastric pain and suspected pancreaticobiliary tract disease. 7.Biliary and pancreatic disorders requiring collection of bile and pancreatic fluid or Oddi sphincter manometry. 8. Those who need endoscopic treatment for pancreaticobiliary disorders. 9.Pancreatic duct rupture is suspected after pancreatic trauma. 10.Suspected bile duct surgery with accidental injury. 11.Suspected congenital lesions of the pancreas. 12, bile duct cancer (common bile duct, hepatic portal and gallbladder); 13, cholelithiasis (common bile duct, gallbladder, and intrahepatic bile duct); 14, intrahepatic bile duct disorders (cholangitis); 15, biliary system stricture and dilatation nature and degree; 16, certain liver disorders. Contraindications to ERCP 1. Upper gastrointestinal strictures and obstruction, which are not expected to reach the descending duodenum. 2. Contraindications to other endoscopic examinations such as cardiopulmonary insufficiency. 3.Non-stone embedded acute pancreatitis or acute attack of chronic pancreatitis. 4.Patients with bile duct stricture or obstruction who do not have bile duct drainage technique. 5.For those who are allergic to iodine contrast agent, non-ionic contrast agent can be used instead, and emergency preparations should be made before surgery. 6, severe bile duct infection ERCP complications are less common, with an incidence of about 2%-4%, mainly biliary ductitis, sepsis, papillary and bile duct injury and acute pancreatitis.