To evaluate the possibility of employing ligustrazine in the prevention of restenosis, the effects of ligustrazine on the intimal thickening of air-injured carotid artery of rats were investigated, and the effects of ligustrazine on the proliferation of rabbit aortic median smooth muscle cells (SMCs) cultivated in vitro were examined. Artery injury model of 18 rats of about 3 months old was established by Fishman air-dry method. Fourteen days after operation, the maximal artery intimal and medial thickness of the control and ligustrazine group was measured on the image analysis system. Using cell counting and thymidine (3H-TdR) up-take method, we also examined the effects of ligustrazine on the proliferation of aortic median SMC from 4 rabbits. Ligustrazine was found to inhibit the proliferation and 3H-TdR up-take of SMC in a dose-dependent manner in vitro (P<0.05 or P<0.01 vs control). It also inhibited the intimal thickening of rat arteries after deendothelialization. The maximal intimal thickness of ligustrazine group was much thinner than that of the control (35.9±3.8 μm vs 80.2±23.4 μm, P<0.01). It was showed that ligustrazine could be used for prevention of restenosis in clinical practice.