Background: It has been shown that administration of statins reduced the risk of peri-procedural myocardial damage. However, it remains unclear whether Chinese medicine Danlou Tablet (a(1)e'OEc parts per thousand double dagger), similar to statins, may protect patients undergoing percutaneous coronary intervention (PCI) from peri-procedural myocardial damage. Objective:To demonstrate the hypothesis whether treatment with Danlou Tablet would improve clinical outcome in patients undergoing selective PCI with non-ST elevation acute coronary syndrome (NSTE-ACS) in China. Methods: Approximately 220 patients with unstable angina or non-ST-segment elevation myocardial infarction undergoing PCI will be enrolled and randomized to Danlou Tablet treatment (4.5 g/day for 2 days before intervention, with a further 4.5 g/day for 90 days thereafter) or placebo. All patients will not receive Danlou Tablet before procedure. The primary end point is to evaluate the incidence of cardiac death, myocardial infarction or unplanned re-hospitalization and revascularization after 30 days in patients undergoing selective PCI treated with Danlou Tablet compared with placebo. Secondary endpoints include the incidence of peri-procedural myocardial injury, 3-month clinical outcomes, the quality of life and Chinese medicine syndromes assessment. Conclusion: This study protocol will provide important evidence of Danlou Tablet treatment on the peri-procedural myocardial injury in patients with NSTE-ACS undergoing selective PCI, which may support a strategy of routine Danlou Tablet therapy to improve the clinical outcomes.