ObjectiveTo establish a mouse model of acute necrotizing pancreatitis.MethodsThirty-six male ICR mice were randomly divided into control group (n=6) and experimental group (n=30). Each of the animals in the experimental group received 7 intraperitoneal injections of caerulein (50 μg/kg body weight) in 0.9% NaCl at hourly intervals over 6 hours. The animals in the experimental group were killed at 9,18,24,48 and 72 hours respectively after the first caerulein injection. The control animals received the same volume of 0.9% NaCl without caerulein. The animals in the control group were killed at the 18th hour after the first intraperitoneal injection. The severity of acute necrotizing pancreatitis was evaluated in terms of amylase level, pancreatic weight/body weight and the histological changes. Variance analysis was employed in the processing of these data. ResultsBoth amylase level and pancreatic weight elevated 9 hours after the first caerulein injection, and correlated with the course of pancreatitis. The maximums of both alterations were observed at the same time point (18 hours after the first injection of caerulein). Prominent interstitial inflammation and acinar cell necrosis occurred at the 18th hour, and the histological score for pancreatitis reached a maximum （P＜0.05）. Conclusion Intraperitoneal injection of a large dosage of caerulein can induce acute necrotizing pancreatitis in ICR mice. This method is simple and noninvasive, and the model established thus is stable and reproducible.