AIM: Available experimental evidence from both clinical andanimal models shows that both Chinese medicines tetrandine(Tet) and Qing Yi Tong (QYT) have positive treatment effectson acute pancreatitis (AP). This investigation was conductedto explore the treatment mechanisms of Tet and QYT on APat the molecular level and thereby explain their therapeuticaffects. It included an invest igation of the effects of thesedrugs on gene expression of both intercellular adhesionmolecule 1 (ICAM-1) and superoxide dismutase (Mn-SODand Cu, Zn-SOD) in a rat model with ARMETHODS: AP in the test rats was induced by subjectingthem to laparotomy followed by a retrograde injection of 4 %sodium taurocholate into the bilio-pancreatic duct. The testrats with AP were divided into three groups. One was treatedwith Tet, one with QYT, and one with normal saline solution.The sham-operated control group (SO) rats were only subjectedto laparotomy. They were given no further treatment. For theTet group, Tet was injected intraperitoneally, and for the QYTgroup, QYT was given with a nose-gastric catheter. Theseprocedures were done at both 10 min and 5 h after APinduction. The levels of ICAM-1 mRNA expression and ofSOD (Mn-SOD and Cu, Zn-SOD) mRNA expression in thepancreas and liver tissues were measured by RT-PCR at 1,5, and 10 h after AP induction.RESULTS: When compared with the SO group during theobservation time, rats with AP showed a higher expressionof ICAM and a lower expression of Mn-SOD in both pancreasand liver tissues, and a lower expression of Cu, Zn-SOD inthe pancreas. Tet treatment attenuated changes in theexpression of both ICAM-1, and SOD (Mn-SOD and Cu, Zn-SOD) to a significant degree. A similar effect on theexpression of SOD (Mn-SOD and Cu, Zn-SOD) was also foundin the QYT group, but no obvious suppressive effect onICAM-1 expression was observed.CONCLUSION: The results of this study suggest that oneof the main mechanisms of Tet and QYT in treating AP is toenhance anti-oxidation of the body. The results also suggestthat the anti-inflammatory effect of Tet is involved in thereduction of ICAM-1 expression. This explains why Tet andQYT are beneficial in treating AP.