The course of a first attack of acute pancreatitis was evaluated in a retrospective study of 602 patients, who were admitted between 01.01.1980 and 30.09.1993 to the Centers of Internal Medicine and Surgery of the University of Göttingen (n = 417) and from 16.11.1986 to 30.06.1994 to the Municipal Hospital of Lüneburg (n = 185). Etiology was biliary tract disease in 227 (37.7%), alcohol abuse in 177 (29.4%), unknown in 133 (22.1%), and other causes in 65 (10.8%) patients. Mean hospital stay was 27.9 +/- 24 days (x +/- SD), median 23 days. Pancreatic pseudocysts developed in 14.3% of the patients, and surgical treatment was necessary in 11.1%. Within the first 48 hours, respiratory insufficiency was observed in 63.2% of the 204 patients undergoing arterial blood gas analysis while renal impairment occurred in 32.6% of 602 patients. Artificial ventilation was indicated in 12.5%, and dialysis in 7% of the patients. Mortality rate was 6.1%, correlating significantly with respiratory and renal impairment and procedures in connection with these complications and also with transfers from other hospitals.