The natural course of the classical symptoms of chronic pancreatitis, i.e. pain, exocrine and endocrine pancreatic insufficiency, was followed up in 335 patients over a median of 9.8 years (mean 11.3 +/- 8.3 years). Pain relief was not obtained in the majority of patients, even after a long-term observation of > 10 years, and severe exocrine/endocrine insufficiency, severe duct abnormalities and pancreatic calcifications developed. Alcohol abstinence failed to have a significant beneficial effect on pain. Pancreatic surgery led to pain relief immediately after operation, but later on the pain course between operated and nonoperated patients was not significantly different. Repeated exocrine pancreatic function tests in 143 patients showed that functional exocrine impairment came to a standstill (46%), or improved (11%). At the end of observation, 22% of 335 patients still had normal endocrine function and only 40% required insulin treatment. Alcohol abstinence had a significant beneficial effect on endocrine, but not on exocrine pancreatic insufficiency. Chronic pancreatitis led to a sharp increase in unemployment and retirement. Pancreatic carcinoma occurred in 3% and extrapancreatic carcinoma in 4%. The mortality rate within the observation period was 22%, pancreatitis-induced complications accounted for 13% of these deaths.