Objective To study the functional mechanism of Naoxin tong Capsule （Ca psule for cerebral and heart diseases） on a cute coronary syndrome （ACS）. Methods Totally 105 ACS p atients diagnosed with coro nary angiography were randomized into a treatment group （55 cases）

and a control group （50 cases）. The control group was treated routin ely with western medicine while the treatment group treated with Naoxintong Capsule

2 capsules each time

3 times a day

in addition to the routine western medicine. Before and 4 weeks after treatment

the serum hypersensitive C-react ive protein （hs-CRP） was measured. Before and six months af ter treatment

changes of carotid intima-media thickness （IMT） and carot id plaque were examined with Color Doppler Ultrasonography. Resu lts Four weeks after treatment

the hs-CRP level in the treatment grou p was significantly lowered than before treatmen t

and the effect was more significant than that of the control group （P<0. 01 ）. Six months after treatment

the IMT of the carotid of both sides was signific antly lowered and the size of carotid plaque became significantly smaller

showi ng a significant difference from before treatment and the control group （P< 0.01 ）. Conclusion Naoxintong Capsule is effective in loweri ng the level of hs-CRP

improvin g the status of carotid intima

and stabilizing the carotid plaque

which is pos sibly one of the functional mechanisms in the treatment of ACS patients.