Coronary heart disease patients must strictly quit smoking after implantation of cardiac stents. Although the implantation of stents can, to a certain extent, solve the problem of localized coronary artery stenosis in patients with coronary artery disease, if they continue to smoke, the harmful substances in cigarettes, such as tar and nicotine, will damage the endothelium of the blood vessels, leading to the occurrence of in-stent restenosis, or even complete occlusion of the in-stent may occur. In addition, these ingredients can also induce sympathetic excitation, stimulate vasoconstriction, increase myocardial oxygen consumption, thereby inducing myocardial ischemia, leading to increased atherosclerosis. Therefore, patients with coronary heart disease, whether or not implanted stents, should not smoke, and usually should pay more attention to rest, eat a light diet, moderate exercise.