Nonbiliary, nonalcoholic pancreatic inflammatory disease was investigated by biochemical investigation, ultrasonography, endoscopic retrograde cholangiopancreatography, and secretin tests. Twenty-five consecutive cases were followed up for 12 months to 10 years after treatment of disease associated with pancreas divisum, diagnosed by endoscopic retrograde cholangiopancreatography. Thirteen patients had no recurrence of acute pancreatitis after dorsal duct sphincterotomy alone, during long-term follow-up (mean, 54 months); one patient had recurrent pancreatitis during 33 months after failed sphincterotomy. Eight patients had variable results 12 months to 8 years (mean, 49 months) after dorsal duct sphincterotomy for pancreatic pain syndrome (without amylase elevation), three were pain free, and one had recurrent pancreatitis. For 10 years after dorsal duct sphincterotomy for chronic pancreatitis, one patient had no pain relief; after subtotal pancreatectomy and pancreaticojejunostomy of the dorsal duct, both for chronic pancreatitis, one patient each was pain free and normoglycemic after 54 and 12 months, respectively. Dorsal duct sphincterotomy alone is successful in achieving long-term freedom from recurrence of acute pancreatitis associated with pancreas divisum. Pancreatic pain syndrome is not consistently improved by dorsal duct sphincterotomy. Chronic pancreatitis associated with pancreas divisum should be treated by resection or drainage procedures, not by dorsal duct sphincterotomy.