Fourteen patients with suspected chronic alcoholic pancreatitis (CAP) and 21 patients who had been shown to have the disease were followed up by the pancreozymin-secretin test in order to clarify the serial changes in exocrine pancreatic function in alcoholic pancreatitis. The initial and final test data for secretory volume, maximal bicarbonate concentration, bicarbonate output (BO), and amylase output (AmO) of exocrine secretion were compared in these two groups. Patients with suspected CAP showed a significant serial decrease only in AmO; definite CAP developed in 3 of them during the follow-up period. In definite CAP, a significantly progressive decrease in BO as well as AMO was observed. It is suggested that in the earlier stage of CAP, AMO is initially affected, whereas decreased secretion of both bicarbonate and enzyme becomes apparent in the later stage.