We studied the effect on the rat pancreas of a choline-deficient diet supplemented with ethionine administered over different time periods. The study was carried out in several groups of male Wistar rats weighing 300 gm and fed for 60, 104, 195, 250, and 336 hours with a choline-deficient diet supplemented with ethionine (CDE). Analysis of pure exocrine pancreatic secretion in animals fed the CDE for 60 hours revealed a decrease in total protein, amylase, and trypsin as compared with animals fed a standard diet. After cholecystokinin stimulation, a gradual decrease in secretion was observed as the duration of the CDE was increased, such that after 336 hours no response to cholecystokinin was found, indicating the lack of pancreatic functionality. Analysis of pancreas preparations by light microscopy showed the existence of infiltration, edema, and hemorrhagic foci after 60 hours of CDE administration. As the duration of the treatment increased, pancreatic morphology deteriorated, with the appearance of vacuolization and foci of necrosis at 195 hours. This deterioration became more pronounced after 250 to 336 hours, progressing to a considerable degree of hemorrhage and necrosis of the acinar tissue. These results clearly confirm the existence of acute necrotizing and hemorrhagic pancreatitis in rats fed a CDE for 250 to 336 hours.