A striking pancreatic juice reflux toward the biliary tree (PR) has frequently been found in subjects with common bile-pancreatic conduit (CBPC) and gallstone-induced acute pancreatitis (SAP). Our aim was to determine the role of the CBPC functional diameter as a potential trigger of PR. The CBPC was calibrated in three groups of patients: (A) patients with gallbladder stones using intraoperative direct cholangiometry (n= 24), (B) patients after surgical removal of common bile duct stones using postoperative cholangiometry via T-drain (n= 6), and (C) patients with SAP using the same procedures as in group B (n= 6). In all patients in groups B and C, aliquots of bile were collected and assayed for pancreatic amylase content. The mean functional diameter of the CBPC varied from 0.80 mm in patients in groups A and B to 0.47 mm in group C (p< 0.001). The bile samples of group B contained low concentrations of amylase, whereas high values could be found in all samples of group C. We conclude that PR is a frequent event occurring after bile duct revision concerning small amounts of pancreatic juice. However, CBPC functional stenosis as seen in patients with SAP obviously induces PR with high amounts of pancreatic juice.