Objective: To investigate the clinical efficacy and the possible mechanisms of Chaixie Danshen decoction in treating unstable angina pectoris (UAP) patients of Qi stagnation and blood stasis type. Method: Eighty-two patients with UAP were randomly divided into observation group (42 cases) and control group (40 cases). Patients in both groups received conventional western medical treatment

and patients in observation group added Chaixie Danshen decoction. All patients received 6 weeks of treatment. The clinical efficacy and the change of Chinese medical syndrome between the two groups were compared before and after treatment. The serum levels of high-sensitivity C-reactive protein (hs-CRP)

tumor necrosis factor alpha (TNF-a)

interleukin 6 (IL-6) and matrix metalloproteinase-9 (MMP-9) were observed before and after treatment. Result: The total curative rate of the observation group (90.48%) was better than that (70.00%) of the control group (P<0.05). The total scores of Chinese medical syndrome and the single score for chest pain

chest tightness

breathe hard

palpitations after treatment were lower than those before treatment in two groups;score changes in observation group were superior to that in control group (P<0.01). The effective rate of Chinese medical syndrome in the observation group (92.86%) was better than that (67.50%) in the control group (P<0.05). Compared with before

the levels of hs-CRP

TNF-α

IL-6 and MMP-9 were significantly decreased in two groups (P<0.05 or P<0.01)

and the observation group obtained better results (P<0.05). Conclusion: Chaixie Danshen decoction could improve symptoms in UAP patients of Qi stagnation and blood stasis type and reduce the levels of hs-CRP

TNF-α

IL-6 and MMP-9.These findings indicate that Chaixie Danshen decoction may have anti-inflammation and anti-atherosclerosis by regulating the levels of inflammatory cytokines of patients with UAP.