Previous studies have demonstrated that Xuezhikang, an extract of cholestin, available from Chinese red yeast rice, could effectively modify lipid profile. The present study was undertaken to investigate whether Xuezhikang could modify endothelin-1 (ET-1), interleukin-6 (IL-6), high-sensitivity C-reactive protein (CRP) and exercise-induced ischemia in patients with cardiac syndrome X (CSX). Thirty-six patients with CSX were randomly assigned to 1200 mg/d of Xuezhikang or placebo group (n=18 respectively). Blood samples were drawn at day 0 and day 90 for measuring above parameters. The treadmill exercise tests and subjective feelings were also assessed at day 0 and day 90. The data showed that Xuezhikang therapy resulted in significant reductions in total cholesterol (TC, 19%), low-density lipoprotein cholesterol (LDL-C) (26%), and triglycerides (TG) compared with baseline (16%, p<0.01 respectively). The data also showed that Xuezhikang led significantly to reductions in median and log-CRP levels (38% and 44%, p<0.01 respectively), IL-6 (20%, p<0.01), and ET-1 (47%, p<0.01) compared with baseline. The exercise duration, and time to 1 mm ST-segment depression was significantly prolonged after Xuezhikang therapy (9% and 6%, p<0.05 respectively) accompanied by improvement of subjective feelings. Data suggested that the benefit of Xuezhikang resulted in significant modification vascular function by reduction of ET-1, inflammatory markers and LDL cholesterol, which may be clinically important for patients with CSX.