Abstract: AIM To investigate the efficacy and safety of nicorandil in the treatment of patients with coronary artery spasm. METHODS 50 patients with coronary artery spasm were randomly divided into a control group and a treatment group. The control group was given routine therapy, including antiplatelet and lipid therapy and the treatment group had routine therapy combined with nicorandil 5 mg, 3/d. Clinical therapy effects of the two groups and endothelial function were determined (the content of NO and endothelin-1) before and after treatment and drug safety was observed. RESULTS Compared with the control group, the clinical effects were clearly superior in the treatment group (P<0.05). After treatment, the NO content was increased (P<0.05), and the content of ET-1 was decreased (P<0.05) in the control group; After 3 months of treatment with nicorandil, the content of NO was increased significantly (P<0.01) and the ET-1 content was significantly decreased (P<0.01). Compared with the control group, treatment with nicorandil for 3 months increased the NO content (P<0.01), and decreased the ET-1 content significantly (P<0.01). The treatment group had only 1 adverse effecxt of mild headache which was tolerated by the patient. CONCLUSION Nicorandil has good efficacy and safety in the treatment of patients with coronary artery spasm.