A total of 108 patients with a normal pancreaticobiliary junction who had gallbladder wall thickness as shown by ultrasonography or computed tomography underwent secretin injection magnetic resonance cholangiopancreatography. Based on the changes in the diameter of the biliary system after secretin injection, patients were categorized into the intensified group (n = 19) or the non-intensified group (n = 89). The mean (±SD) biliary amylase level in the bile duct was 41674 (±59779) IU/L in the intensified group, which was significantly higher than that in the non-intensified group (210 (± 418)) IU/L (p<0.0001). There were four patients with carcinoma of the gallbladder in the intensified group and their biliary amylase level in the bile duct was 90783 (±82528) IU/L. Pancreatobiliary reflux similar to that seen in patients with pancreaticobiliary maljunction can occur in persons with a normal pancreaticobiliary junction and this may be associated with carcinoma of the gallbladder. Secretin injection magnetic resonance cholangiopancreatography proved useful to identify such persons.