Pancreatic hyperstimulation with simultaneous duct obstruction does not cause the typical features of acute pancreatitis, therefore the role of an additional challenge, such as either ethanol intoxication or short-term ischemia, was studied. Alcoholic pancreatitis was induced in 28 rats by acute ethanol intoxication (0.25 LD50) and an obstruction/hyperstimulation mechanism (clip of the biliopancreatic duct for 20 min and intravenous stimulation with 5 U of cholecystokinin and secretin each). Ischemic pancreatitis was performed by obstruction/hyperstimulation and subsequent pancreatic ischemia by clamping the supplying arteries for 40 min. The macro- and microscopic alterations were evaluated and graded by a scoring system. Additionally, the pancreas was removed in 50% of the animals and the pancreatic acini were prepared. From those acini the intracellular enzymes trypsinogen, kallikreinogen, amylase, lipase, glucuronidase, and acidic phosphatases were determined. While obstruction/hyperstimulation, 40 min of ischemia, or ethanol alone did not induce acute pancreatitis, a combination of obstruction/hyperstimulation with either ethanol or ischemia resulted in acute pancreatitis in 68 and 60% of treated rats, respectively. Similarly, both models were characterized by extrapancreatic fat necrosis and acinar necrosis at the periphery of the lobules. Almost all intracellular enzymes were elevated in both pancreatitis models compared to sham-operated controls. Both alcohol and ischemia were insults that sensitize the pancreas to develop acute pancreatitis after obstruction/hyperstimulation. Since the observed morphologic and enzymatic alterations in both models are very similar, alcohol and ischemia might have some common pathways by which they make the pancreas vulnerable to enzymatic attacks.