Abstract: Objective: The study investigate probucol combined with simvastation endothelial function in patients with acute coronary syndrome(ACS). Method :A total of 60 ACS patients randomly received standard therapy plus simvastatin (A,n=30) or standard therapy plus probucol combined with simvastatin (B,n=30). Plasma oxidized low-density lipoprotein(ox-LDL) and nitric oxide(NO) were measured.The brachial arterial hyperemia-induced flow mediated dilation(FMD) mediated vasodilatations were measured by high resolution ultrasound. These variables were analyzed before and after 3 months. Results: the difference of Plasma ox-LDL before and after the treatment between the two groups were lower in A group than in B group, had statistically significant(t=30.681,P<0.001). the difference of Plasma NO before and after the treatment between the two groups were rised in A group than in B group ， had statistically significant(t=17.3403,P<0.001).the difference of FMD before and after the treatment between the two groups were rised in A group than in B group ， had statistically significant(P<0.001).Conclusion: Simvastatin combined with ntioxidant probucol therapy could improve endothelial function in patients with acute coronary syndrome.

Key words: acute coronary syndrome, endothelium antilipemic agents probucol