Abstract: Objective: To observe the changes in gut mucosal barrier in rats with acute necrotizing pancreatitis(ANP).Methods: SD rats were randomly divided into sham operation group(n=40) and ANP group(n=40).The rat models of ANP were set up by retrograde injection of 5% sodium taurocholate in the biliopancreatic duct.The morphological changes of pancreas and ileum were observed.Plasma levels of intestinal fatty acid binding protein(IFABP) and endotoxin were examined at various time points,the bacterial translocation rates of mesenteric lymph nodes and portal vein were also examined at various time points.Results: The plasma levels of IFABP were elevated obviously 2 hours after ANP induction and reached peak value at 6 hours(P<0.01)and decreased at 24 hours.Plasma endotoxin levels also increased significantly at the early stage of ANP and reached peak value at 48 hours (P<0.01).The rates of bacterial translocation to mesenteric lymph nodes increased sharply 24 hours after SAP induction and reached six-eighths at 48 hours(P=0.013).The bacterial translocation rates of portal vein reached three-eighths at 48 hours(P=0.216).Conclusions: Gut mucosal barrier function can be injured in the early stage of ANP,and result in gut origin bacteria-endotoxin translocation,which may be the originator of septic and secondary infection of the pancreas.IFABP may be a specific marker for identification of gut mucosal barrier dysfunction in the early stage of ANP.