Recently, high-dose short-term alcohol exposure has been observed not to induce acute pancreatic damage, as evaluated by serum pancreatic enzyme activities. In this study the effect of high-dose, long-term alcohol exposure on the pancreas was investigated in 32 consecutive alcoholics admitted to a unit to treat the problems of withdrawal after a long period of heavy drinking. None of the alcoholics complained of abdominal symptoms. The signs of clinical acute pancreatitis (pain, increased serum C-reactive protein concentration or blood white cell count) were not observed in any of the alcoholics. A significant increase in serum total amylase, pancreatic isoamylase and lipase activities developed by the second day after termination of alcohol intake. These enzyme activities remained significantly increased for one week after cessation of drinking. Seven alcoholics had signs of chronic pancreatitis at ultrasonography (pancreatic calcification, pseudocyst). These results suggest that heavy alcohol intake over the long term may frequently induce subclinical pancreatic injury.