Background: Traditional Chinese medicine (TCM), especially herbal medicine, has been widely used in China and now is also being incresingly used in other countries for the treatment of cardiovascular diseases. Although many studies have demonstrated that certain Chinese herbal products are effective and safe for the treatment of cardiovascular diseases, most of these lack sufficient quality. Therefore, large randomized clinical trials and further scientific research to determine ist safety, effectiveness are necessary QiShen YiQi Dripping Pills (QSYQDP) is a herbal preparation clinically used in the treatment and prevention of coronary artery disease. Preliminary observations have shown its safety and effectiveness. Methods/Design: This randomized, controlled trial will recruit 3600 patients with a history of myocardial infarction. Patients will be randomized into two groups by a Centr-Randomized System. One group receivcs QSYQDP, the other group receive aspirin. This trial protocol will describe eligibility criteria, detailed information on the treatment definition, blinding, endpoints, statistical methods, sample size ditermination, data management, legal aspects, and the current status of the trial. Discussion: This trial is one of the first randomized, controlled clinical trial to evaluate the results of this study should help to difine the role of TCM in modern medical care, as well as to provide the management strategy for CAD patients in China and other countries. (J Geriatr Cardiol 2006; 3 (2): 116-9.)