Acute pancreatitis usually subsides spontaneously or is complicated by pseudocysts, pancreatic necrosis, or abscesses. We describe an uncommon variant of acute pancreatitis in which signs of inflammation persist over a number of months, waxing and waning but never disappearing. Neither identifiable collections nor other targets for surgical drainage develop in these patients, nor does their condition ever remit enough to allow them to leave the hospital. Eating provokes a flareup of inflammation. We have treated five such patients with a pancreatoduodenectomy (four patients) or total pancreatectomy (one patient). Each patient had been continuously hospitalized for six to 12 weeks before operation. All survived the operation and left the hospital eating solid food within 16 days. In addition to acute inflammation and fat necrosis, the resected specimens showed main pancreatic duct stenosis or occlusion in three patients, a pancreaticoduodenal fistula in one, and a congenital duplication cyst. Pancreatography or cholangiography showed the lesion in three of four cases and helped in planning therapy. Thus, acute pancreatitis may fall to remit because of proximal pancreatic duct obstruction, for which pancreatoduodenectomy is a reasonable and effective treatment.