To evaluate the safety and efficacy of Xiongshao Capsule (eSZeSie integral a > S, XS), consisting of Chuangxiongol and paeoniflorin, in preventing restenosis after percutaneous coronary intervention (PCI) in senile coronary heart disease (CHD) patients. A multi-center, randomized, double-blind, placebo-controlled trial was conducted. A total of 335 CHD patients were randomly assigned to treatment with oral administration of XS, or a placebo for 6 months after successful PCI. A clinical follow-up was performed at 1, 3 and 6 months after PCI and an angiographic follow-up was scheduled at 6 months. The primary endpoint was angiographic restenosis defined as a luminal stenosis a (c) 3/4 50% in follow-up. The secondary endpoints were combined incidence of death, target lesion nonfatal myocardial infarction, repeat target-vessel angioplasty, and coronary artery bypass graft surgery (CABG). The follow-up for the above clinical endpoint events was continued to 1 year after PCI. The subgroup analysis of 152 senile patients (68 cases angiographic follow-up) showed that the restenosis rates tended to reduce in the XS group as compared with that in the placebo group (24.32% vs. 38.71%, P > 0.05), and the minimum lumen diameter (MLD) significantly increased in the follow-up (2.15 +/- 0.84 for XS vs. 1.73 +/- 0.91 for placebo, P < 0.05). The incidence of recurrent angina at 3 and 6 months after PCI was also significantly reduced in the XS group (4.11% and 12.33%) as compared with those in the placebo group (17.72% and 43.04%), but there was no significant difference in the combined incidence of clinical outcomes (6.85% in the XS group vs. 11.39% in the placebo group, P > 0.05). No significant adverse reactions occurred within the 6-month follow-up period in the XS group. Administration of XS in addition to standardized Western medication for 6 months is demonstrated to be safe and effective in reducing post-PCI recurrent angina and inhibiting luminal restenosis after PCI in senile CHD patients.