Background: The common channel theory suggests that bile reflux, through a common biliopancreatic channel, triggers acute pancreatitis. In the present study, this controversial issue was evaluated using an experimental model of hemorrhagic necrotizing pancreatitis. Methods: American opossums underwent ligation of the pancreatic duct alone, bile and pancreatic duct separately, or common biliopancreatic duct; the severity of pancreatitis was evaluated at selected times after ligation. Results: Animals in all three experimental groups developed hemorrhagic necrotizing pancreatitis; the severity of pancreatitis was similar in each group, although only those subjected to common biliopancreatic duct ligation experienced bile reflux. Conclusions: Bile reflux into the pancreatic duct, via a common biliopancreatic channel, is not necessary for the development of pancreatitis and does not worsen the severity of pancreatitis associated with pancreatic duct obstruction in this model.