Objective To investigate the clinical efficacy of Xinxuetong Oral Liquid in the treatment of patients with acute coronary syndrome(ACS).Methods A total of 80 patients with ACS of blood stasis syndrome who were hospitalized in Shunde Hospital of Guangzhou University of Chinese Medicine from January 2023 to September 2023 were randomly divided into the treatment group and control group according to random number table method,40 patients in each group.The patients in the two groups were given conventional western medicine treatment including lifestyle guidance,percutaneous coronary intervention(PCI),and conventional western medicine therapy.Additionally,the treatment group was treated with Xinxuetong Oral Liquid.The course of treatment for the two groups covered eight weeks.Before and after treatment the two groups were observed in the changes of traditional Chinese medicine(TCM)syndrome score,blood stasis syndrome score,angina pectoris score,blood lipid indicators,carotid ultrasonography indicators,echocardiography indicators,and serum levels of trimethylamine-N-oxide(TMAO),nitric oxide(NO),endothelin 1(ET-1),interleukin 8(IL-8),serine/threonine-protein kinase 1(AKT-1),and vascular endothelial growth factor A(VEGF-A).After treatment,the efficacy on TCM syndrome efficacy and the safety of the regimen in the two groups were evaluated.Results(1)During the trial,there were two cases of loss to follow-up and one case of withdrawal due to pneumonia,and eventually a total of 77 patients completed the full course of treatment,among which 39 patients were in the treatment group and 38 patients were in the control group.(2)After eight weeks of treatment,the total effective rate of the treatment group was 89.74％(35/39),and that of the control group was 63.16％(24/38).The intergroup comparison(tested by chi-square test)showed that the effective rate of TCM syndrome efficacy in the treatment group was significantly superior to that in the control group(P＜0.01).(3)After treatment,the scores of TCM symptoms such as chest pain,chest distress,symptom aggravation at night,and palpitation in the two groups,as well as the score of gloomy complexion in the treatment group,were significantly decreased compared with those before treatment(P＜0.05 or P＜0.01),and the decrease of scores of chest distress,symptom aggravation at night,and palpitation in the treatment group was significantly superior to that in the control group(P＜0.05 or P＜0.01).(4)After treatment,the blood stasis syndrome score and angina pectoris symptom score of the two groups of patients were significantly decreased compared with those before treatment(P＜0.01),and the decrease in the treatment group was significantly superior to that in the control group(P＜0.01).(5)After treatment,the serum TMAO,ET-1,IL-8,AKT-1,and VEGF-A levels in the two groups were significantly decreased compared with those before treatment(P＜0.01),and the serum NO level was significantly increased compared with that before treatment(P＜0.01).The decrease of serum TMAO,ET-1,IL-8,and AKT-1,VEGF-A levels and the increase of serum NO level in the treatment group were significantly superior to those of the control group(P＜0.05 or P＜0.01).(6)After treatment,the total cholesterol(TCHO)and low-density lipoprotein cholesterol(LDL-C)levels of the two groups(P＜0.01)and the triglyceride(TG)level of the treatment group(P＜0.05)were decreased significantly compared with those before treatment,while the high-density lipoprotein cholesterol(HDL-C)level of the treatment group was increased significantly compared with that before treatment(P＜0.01).No obvious changes of TG and HDL-C levels before and after treatment were shown in the control group(P＞0.05).The comparison of blood lipid indicators after treatment between groups showed that there were no statistically significant differences(P＞0.05).(7)After treatment,the carotid ultrasonography indicators of carotid intima-media thickness(IMT)and Crouse score of the carotid plaque in the two groups were significantly improved compared with those before treatment(P＜0.01).However,there was no statistical significance in the comparison of the two indicators between the two groups after treatment(P＞0.05).(8)The observation of echocardiography indicators showed that only the post-treatment left ventricular diameter(LVd)of the treatment group was significantly larger than that before treatment(P＜0.05),while no obvious changes of the other echocardiography indicators before and after treatment were shown in the two groups(P＞0.05).The comparison between the groups after treatment also showed no statistically significant differences(P＞0.05).(9)During the treatment,no serious drug-induced adverse reactions or drug-related severe cardiovascular events and complications occurred in the two groups.Conclusion The combination of Xinxuetong Oral Liquid with conventional western medicine treatment exerts certain efficacy and safety on improving the clinical symptoms of patients with ACS of blood stasis syndrome,and its therapeutic mechanism may be related to the improvement of blood lipid levels,inflammatory response,and TMAO level.