In 38 patients, exocrine pancreatic function was tested by means of the secretin-pancreozymin test (SPT) and pancreatic duct system with endoscopic retrograde cholangiopancreatography (ERCP) 34 +/- 36 mo (mean +/- SD, range 1-156 mo) following acute pancreatitis. SPT and ERCP results were both normal in 19 (50%). They were both abnormal in four (11%) patients (group 1). Fourteen (37%) patients with normal SPT had abnormal ERCP test results (group 2), and one (3%) patient with normal ERCP had abnormal SPT (group 3). All patients except one of group 2 could be followed up within a mean observation time of 105 +/- 46 mo (range 24-168 mo): Chronic pancreatitis developed in all four patients of group 1, in one patient of group 2, and in the single patient of group 3, and suspected chronic pancreatitis in another patient of group 2. Eleven of the remaining 12 patients with abnormal ERCP results, but normal exocrine pancreatic function (group 2), showed no signs or symptoms of acute or chronic pancreatitis. It is concluded that (1) recovery to normal does not necessarily occur after acute pancreatitis, (2) progression to chronic pancreatitis is possible at a considerable percentage, and (3) duct changes demonstrated by ERCP may persist without any later signs and symptoms of acute or chronic pancreatitis.