Objective To discuss the mechanism of Shenqing Fang in treatment on ulcerative colitis（UC）.Methods The rat model of UC was established by the enema of TNBS in rats.SD rats（n=60） were randomly divided into normal group

model group 1

model group 2

mesalazine group

low-dose Shenqing Fang（low-dose group） and high-dose Shenqing Fang（high-dose group

each n=10）.The expression of colonic mucosal addressin cell adhesion molecule-1（MAdCAM-1） was detected by applying immnohitological staining

reverse transcription polymerase chain reaction（RT-PCR） and Western-blot test.Results The expression of MAdCAM-1 was lower in normal group

and protein expression and gene transcription were higher in model groups than those in normal group（P<0.01）.The expression of MAdCAM-1 was significantly down-regulated in high-dose group

low-dose group and mesalazine group compared with model group 2（P<0.01）

and the decreasing trend was more significant in high-dose group.Conclusion Shenqing Fang has therapeutic effect on UC

and the mechanism may be related to that it can reduce the expression of MAdCAM-1.