Spreading of injected material and ductal resistance were studied in the rat pancreas after intraductal injection of Indian ink, human serum or sodium taurocholate. Indian ink filled the main pancreatic duct and small ductules revealing the lobular structure in macroscopic preparation. Escape into the interstitium was observed both in the macroscopic preparations and in histologic sections. Human IgG was demonstrated immunohistochemically in single acinar cells and around acinar cells after intraductal injection of human serum. The changes were most pronounced at 15 min and at 6 h after the injection but were almost resolved at 24 h. The intraductal pressure was registered during sodium taurocholate infusion. The pancreatic duct ruptured at the pressure of 82 mm Hg in average. It was concluded that in the ductal model of experimental acute pancreatitis the infusion causes ruptures in pancreatic ducts and the infusate escapes into the interstitium where it remains for several hours.