Background:Coronary artery disease (CHD) now accounts for approximately one third of all deaths globally and up to one-quarter of patients may have either continues or recurrent post-PCI chest pain. Yinxing Mihuan oral solution (YMOS) has been proven to bring clinical benefits for patients with CHD and Ginkgo biloba extract can relieve depression in mice. No high-quality randomized controlled trials on YMOS have been published. The aim of this study is to evaluate the efficacy and safety of Yinxing Mihuan oral solution (YMOS) in the treatment of patients with post-percutaneous coronary intervention (PCI) chest pain. This study also aimed to relieve the symptoms of chest pain as a primary outcome, improve the anxiety as a secondary outcome, assess therapeutic effects of YMOS on chest pain, and explore its effects on chest pain caused by psychological disorders after PCI.Methods: 320 patients with symptoms related to heart and a confirmed history of PCI for coronary heart disease (CHD) without the need to undergo selective coronary revascularization plan were recruited in this randomized controlled trial. The included participants were randomly assigned (at a ratio of 1:1) to experimental group and control group; patients in the experimental group received YMOS and standardized medical treatment, while those in control received placebo (10 ml) for three times/day for 12 weeks and standardized medical treatment regimen. The endpoints of the study included Seattle angina questionnaire (SAQ) score, Hamilton anxiety rating scale (HAMA), Hamilton rating scale for depression (HRSD), Canadian Cardiovascular Society (CCS) angina score, New York Heart Association (NYHA) classification, visual analogue scale (VAS), 12-Item short form survey (SF-12), frequency of angina-related symptoms per week, nitroglycerin discontinuation, and reduction rate of HAMA score.Discussion: This clinical trial can provide reliable evidence regarding the efficacy and safety of YMOS for patients with post-PCI chest pain.Trial registration: This research has been registered at the Chinese Clinical Trial Registry (Registration No. ChiCTR2000028760) on January 1, 2020. http://www.chictr.org.cn/showproj.aspx?proj=47528