Etiologic investigations include serum amylase, lipase, triglyceride and calcium determination, as well as abdominal ultrasound scanning. Alcohol consumption is asked by using WHO audit test. After etiology of acute pancreatitis has been confirmed as idiopathic, 100 patients are randomized to laparoscopic cholecystectomy and 100 patients to follow-up of 2 years. Five to seven Finnish university and main central hospitals are participating the study.