AIM: To evaluate the role of microcirculatory disorder(MCD) and the therapeutic effectivenessof tetramethylpyrazine (TMP) on intestinal mucosa injury in rats with acute necrotizing pancreatitis (ANP).METHODS: A total of 192 Sprague-Dawley rats were randomly divided into three groups: normal control group (C group), ANP group not treated with TMP (Pgroup), ANP group treated with TMP (T group). An ANP model was induced by injection of 50 g/L sodium taurocholate under the pancreatic membrane (4 mL/kg).C group received isovolumetric injection of 9 g/L physiological saline solution using the same method. T group received injection of TMP (10 mL/kg) via portal vein. Radioactive biomicrosphere technique was used to measure the blood flow at 0.5, 2, 6 and 12 h after the induction of ANP. Samples of pancreas, distal ileum were collected to observe pathological changes using a validated histology score. Intestinal tissues were also used for examination of myeloperoxidase (MPO) expressed intracellularly in azurophilic granules of neutrophils.RESULTS: The blood flow was significantly lower in P group than in C group (P ＜ 0.01). The pathological changes were aggravated significantly in P group. The longer the time, the severer the pathological changes.The intestinal MPO activities were significantly higher in P group than in C group (P ＜ 0.01). The blood flow of intestine was significantly higher in T group than in P group after 2 h (P ＜ 0.01). The pathological changes were alleviated significantly in T group. MPO activities were significantly lower in T group than in P group (P ＜0.01 or P ＜ 0.05). There was a negative correlation between intestinal blood flow and MPO activity (r = -0.981,P ＜ 0.01) as well as between intestinal blood flow and pathologic scores (r = -0.922, P ＜ 0.05).CONCLUSION: MCD is an important factor for intestinal injury in ANP. TMP can ameliorate the condition of MCD and the damage to pancreas and intestine.