Patients who are at high risk of post-ERCP pancreatitis, who have at least one of the following factors: clinically suspected sphincter of Oddi dysfunction, history of post-ERCP pancreatitis, pancreatic sphincterotomy, precut sphincterotomy, difficult cannulation, balloon dilatation of intact sphincter, endoscopic ampullectomy, and 2≥minor criteria(an age of less than 50 years and female sex, a history of recurrent pancreatitis (≥2 episodes), three or more injections of contrast agent into the pancreatic duct with at least one injection to the tail of the pancreas, excessive injection of contrast agent into the pancreatic duct resulting in opacification of pancreatic acini,the acquisition of a cytologic specimen from the pancreatic duct with the use of a brush).