The aim of this paper was to evaluate the influence of nifedipine (calcium channel blocker) and Bay-K-8644 (calcium channel agonist) on cerulein acute pancreatitis (AP) in rats. AP was induced according to the Lampel and Kern method (1) by the continuous intravenous infusion of cerulein in the doses of 5 x 10(-6) g/kg/h for 12 hours. There was obtained a statistically significant decrease in serum amylase activity and pancreatic weight in the groups treated with higher doses of nifedipine before infusion of the cerulein compared with rats treated only with cerulein. However, in the group treated with Bay-K-8644 before infusion of cerulein statistically significant increase was obtained in serum amylase activity and pancreatic weight compared with the group treated only with cerulein. The investigations suggest a beneficial effect of higher doses of nifedipine on cerulein induced AP. The inflammatory changes in the pancreas in the groups treated with nifedipine observed under the light microscope were smaller than in the group treated only with cerulein.