Objective:To observe the clinical effect and protection of vascular endothelium of Zhixinkang Capsule (ZXKC) in middle-aged and old people with unstable effort angina and hyperlipidemia.Methods: Sixty-five patients with unstable effort angina were randomly divided into ZXKC group (34 cases)and control group (31 cases). Conventional west medical therapy was given to both groups, with ZXKC group receiving additional ZXKC treatment. Data of 20 healthy persons were taken as normal group. Forty-eight patients with hyperlipidemia were divided into ZXKC group treated with ZXKC (31 cases) and control group treated with Yixintong (17 cases). The changes of clinical symptoms and laboratory indexes in all the patients were observed before and after treatment. Results: In patients with unstable effort angina, the efficacy of treatment of ZXKC, the withdrawal rate of nitroglycerin, the relieving of symptoms, the improvement of the electrocardiogram, the counts of circulating endothelial cells, the content of platelet P-selectin, the content of plasma endothelin (ET), the activity of superoxide dismutase (SOD) and the activity of malonyldialdehyde (MDA) were all better than those in the control group. In patients with hyperlipidemia, there was no significant difference in lipids reduction between ZXKC group and the control group. In both groups, the total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol (LDL-C), lipoprotein(a) [Lp(a)], ET, oxidized low density lipoprotein, MDA, arteriosclerotic index (AI) all lowered obviously, while the SOD, HDL-C and calcitonin gene-related peptide (CGRP) were all elevated markedly. In the ZXKC group, the nitric oxide(NO) increased significantly whereas the ET/CGRP and ET/NO decreased markedly. The total effective rate in symptom relieving, the markedly effective rate, the reduction of TC, ET and ET/CGRP, and the elevation of SOD in ZXKC group were all superior to those in the control group. Conclusion: ZXKC could effectively resist myocardial ischemia, relieve angina, reduce blood lipids, protect vascular endothelial cells, inhibit the activation of platelets, and resist lipid peroxidation.