What is ERCP and what are its indications for the treatment of those diseases? What are its advantages? ERCP (Endoscopic Retrograde Cholangiopancreatograph), the Chinese full name is transduodenoscopic retrograde cholangiopancreatography, the process is the use of duodenoscopy through the oral cavity to the duodenal papilla, through the microscope intubation to the bile duct or pancreatic duct for imaging, and based on the use of a variety of tubes, guide wires, etc. for Based on this, various kinds of tubes and guide wires are used for sphincter dilatation, sphincterotomy, bile duct or pancreatic duct stone removal, bile duct or pancreatic duct drainage, and stent placement, etc., so as to treat bile duct stones, biliary pancreatitis, and obstructive jaundice. Since ERCP utilizes the natural orifice of the upper gastrointestinal tract and does not require any incision in the abdomen, it is less invasive than common laparoscopic surgery. Not only is there no incision or pain, but there is also little interference with the abdominal organs, and you can usually return to eating six hours after the procedure. Compared with the traditional diagnosis and treatment, ERCP has the following characteristics: (1) Through various treatments under ERCP, some diseases can be completely cured without other surgical treatments, such as various types of extrahepatic bile duct stones, biliary ascariasis, papillary sphincter stenosis and so on. (2) Secondary choledocholithiasis after laparoscopic cholecystectomy for gallbladder stones is one of the common clinical situations, and the traditional method is to carry out open or laparoscopic biliary exploration again, place a “T” drain, and then remove the “T” tube 6 to 8 weeks after the operation. The T-tube is removed 6 to 8 weeks after surgery. The ERCP transduodenal papilla biliary lithotripsy avoids the risk and pain of reoperation in the short term, and is the best choice for this case. (3) For patients diagnosed with gallbladder stones combined with secondary stones in the common bile duct before surgery, “two-lens” combined treatment provides an optimal solution. For patients diagnosed with gallbladder stones and common bile duct stones by ultrasound, traditional surgery involves laparotomy or laparoscopy to remove the gallbladder, opening the common bile duct to remove the stones, and placing a “T”-shaped tube to drain the gallbladder for more than 6-8 weeks, which is very damaging to the patient and requires more than 2 weeks of hospitalization. The combination of ERCP and laparoscopy is the best surgical option that utilizes the complementary advantages of the two scopes. First, ERCP is performed, and an electronic duodenoscope is inserted through the oral cavity. After the diagnosis is confirmed by angiography, the stones in the common bile duct are removed by papillary dilatation or incision, followed by laparoscopic cholecystectomy. The patient is discharged from the hospital on the third to fourth day. Combined treatment of cholelithiasis with two scopes is the development trend of biliary surgery, which can replace open surgery for cholelithiasis. (4) It is common to see acute obstructive septic cholangitis due to bile duct stones or tumors, and the patients suffer from jaundice, fever and even life-threatening shock. Usually, it is necessary to perform the first stage of emergency surgery to place a “T” tube for drainage, and then perform the second stage of surgery to remove the stones or tumors completely after 1 to 3 months. However, through ERCP, a transnasal biliary drainage tube or biliary stent can be placed via duodenoscopy to relieve the obstruction, relieve the symptoms and improve the systemic status, and then definitive surgery can be performed to remove the stone or resect the tumor in a short period of time, which avoids the risks and pains of multiple surgeries. (5) For various diseases such as acute biliary pancreatitis and obstructive jaundice caused by tumor around jugular abdomen, after corresponding treatment under ERCP, bile duct and pancreatic duct drainage can be opened to alleviate the clinical symptoms, and the cause of the disease can be further clarified through endoscopic diagnosis, which creates conditions for the next step of treatment. (6) For patients with jaundice due to bile duct obstruction caused by peripelvic tumors such as cholangiocarcinoma, pancreatic head cancer, etc., biliary drains or stents can be placed under ERCP to smooth the bile ducts and alleviate jaundice, and then go into surgical treatment after the surgical safety of the patients has been improved; for the old and weak patients or patients who have lost the chance of resecting the tumor, biliary dilatation can be carried out and biliary stents can be placed under ERCP to relieve jaundice, which can significantly improve the quality of life. Jaundice can significantly improve the quality of life and prolong the life, which can reach or even exceed the effect of palliative drainage surgery, while avoiding the risk and pain brought by traditional surgery. (7) As a complementary treatment after surgery, residual bile duct stones and papillary sphincter stenosis after biliary surgery can be treated by minimally invasive surgery under ERCP.