Pancreas divisum is the most common anatomical variant of pancreatic ductal anatomy. It has been suggested that obstruction at the accessory papilla in subjects with pancreas divisum can be assessed by measurement of ductal diameter by ultrasonic examination after a maximal secretory stimulus with i.v. secretin. We have prospectively assessed this test in 44 individuals; nine healthy controls, nine patients with abdominal pain and normal pancreatic anatomy, 17 patients with pancreas divisum and abdominal pain but no other evidence of pancreatitis, and nine patients with pancreas divisum and either chronic or recurrent acute pancreatitis. We have found no correlation between ductal anatomy and response to i.v. secretin. Secretin provocation tests do not indicate which patients have accessory papillary stenosis and do not add support to the hypothesis of obstruction leading to pancreatitis in patients with pancreas divisum.