Objective: To investigate whether Buyang Huanwu decoction inhibits homocysteine(Hcy)-mediated smooth muscle cell proliferation and related mechanisms. Method: Thirty male mice were treated with Buyang Buyang Huanwu decoction(14.9 g· kg-1· d-1) for 7 days to abtain Buyang Huanwu decoction contained serum

concentration of which was as 5%

10%

20% and added to smooth muscle cells. After 1 hour homocysteine was added and cultured for 24 hours. Cell cycle distribution and the expression of proliferating cell nuclear antigen(PCNA)were detected by Western-blotting

DCFH-DA was used for examining the levels of reactive oxygen species(ROS). Result: Buyang Huanwu decoction could decrease ROS content

significantly inhibited cell cycle of VSMc

as 20% doses make 27.95%(P<0.01)cells at cell cycle of S+G2;and down regulated the expression of PCNA(P<0.01);significantly inhibited ROS production induced by Hcy in VSMCs. Conclusion: Buyang Huanwu decoction significantly inhibit Hcy-mediated proliferation of VSMCs

and inhibition of ROS production may be related molecular mechanisms.