The study described in this report will be approved by the ethics committee of Yonsei University School of Medicine, Seoul, Korea. Between July 2012 and February 2013, 380 patients fulfilled the inclusion criteria, 380 of whom were included in the final analysis. Consecutive patients were recruited for the study who presented to the Yonsei University Medical Center with variable symptom or cause for ERCP older than 20years. Patients were excluded from study participation if they had a contraindication for diclofenac, including patients with recently diagnosed peptic ulcer disease or active/recent gastrointestinal hemorrhage within 4 weeks, renal failure(Cr > 1.4), those who had taken an NSAID during the preceding week(ASA 325 mg daily or less acceptable), those who developed acute pancreatitis during the 2 weeks before ERCP, those with a history of chronic calcific pancreatitis or allergy to aspirin or NSAID, and those who did not agree to participate in the study. Additionally, if state of patients was intrauterine pregnancy or breast feeding mother, they were excluded. Entry to the study was restricted to patients advised to have endoscopic retrograde cholangiography with or without pancreatography for extrahepatic cholestasis and/or impaired liver function tests.