Coronary heart disease is still one of the most common cardiovascular disease and causes of death worldwide (including China). Antiplatelet drugs are fundamental in the treatment of coronary heart disease. In recent years, more and more studies have found that trimethylamine N-oxide (TMAO), a major metabolite of intestinal flora, can promote atherosclerosis through various mechanisms, affecting the prognosis of patients with coronary heart disease and the efficacy of antiplatelet drugs. This article reviews the effect of TMAO on coronary heart disease and the efficacy of antiplatelet drugs.