Aim To observe the effect of atorvastatin combined with probucol on the levels of serum lipids,oxidized low density lipoprotein(ox-LDL) and the activity of paraoxonase-1(PON1) in patients with acute coronary syndrome(ACS). Methods A randomized,open study was performed on a total of 38 patients(including 27 males and 11 females,the average age was 63.7±8.9 years) with ACS.The patients were randomly assigned to a control group(atorvastatin 10 mg/day,n=20) or a treatment group(atorvastatin 10 mg/day and probucol 1 000 mg/day,n=18).All of them were followed up for 4 weeks.Serum levels of total cholesterol(TC),low density lipoprotein cholesterol(LDLC),high density lipoprotein cholesterol(HDLC),triglyceride(TG),ox-LDL and PON1 activity were measured before and after treatment. Results After 4 weeks of treatment,LDLC levels reduced by 15.4% and HDLC increased by 13.7% in the control group compared with baseline(P<0.05),but the decreases in TC and TG were not significant(P>0.05);the serum levels of TC,LDLC,HDLC and TG in the treatment group decreased significantly(-28.1%,-28.5%,-14.2% and-23.3%,respectively,P<0.01 or 0.05);The decline of TC,and HDLC in treatment group was more significant than that in the control group(P<0.01).After treatment,serum ox-LDL levels declined significantly and PON1 activity increased significantly in both groups compared with baseline(P<0.01);The changes of ox-LDL levels and PON1 activity were more significant in the treatment group than those in the control group(P<0.01).No relationships were observed between TC,TG,LDLC,HDLC and ox-LDL or PON1 before and after treatment(P>0.05),but the serum levels of ox-LDL and PON1 had a significant negative correlation by Pearson correlation analysis(r=-0.669,P<0.01). Conclusion The addition of probucol to atorvastatin has a synergistic effect in lowing the cholesterol and antioxidant,but atorvastatin can not offset the HDLC decreasing effect of probucol.