OBJECTIVE: To investigate the protective effects of Shexiang Tongxin dropping pill(麝香通心滴丸,STDP) in a rat model of coronary microcirculatory dysfunction(CMD).METHODS: Sprague-Dawley rats were allocated randomly into four groups: sham, CMD model,STDP, and nicorandil. After 4 weeks of treatment,CMD was induced by injection of sodium laurate(0.2 m L, 2 g/L) into the left ventricle while obstructing the ascending aorta. Rats in the sham group underwent an identical surgical procedure but were administered physiological(0.9%) saline(0.2 m L).Twenty-four hours after surgery, blood samples were collected for biochemical analyses and enzyme-linked immunosorbent assays. Heart tissues were removed for histopathology staining; apoptosis and inflammatory cytokines were examined by Western blotting.RESULTS: The STDP group had a lower level of creatine kinase-myocardial band, lactate dehydrogenase, and cardiac troponin-I than that in the CMD model group. Infiltration of inflammatory cells,myocardial ischaemia, and microthrombosis were relieved in the STDP group compared with CMD model group. Levels of endothelin-1, nuclear factor-kappa B, tumour necrosis factor-α, interleukin-6, interleukin-1β, malondialdehyde, B-cell lymphoma(Bcl)-2-associated X protein, and caspase-3 were lower, and levels of nitric oxide, Bcl-2, and superoxide dismutase were higher, in the STDP group in comparison with the CMD model group.CONCLUSION: STDP pretreatment improved the CMD induced by sodium laurate via anti-inflammatory, anti-apoptosis, and anti-oxidant mechanisms.