Smoking can increase the incidence of coronary heart disease significantly. Because the smoke released when burning tobacco contains more than 3800 kinds of known chemical substances, there are more than 10 kinds of chemicals related to coronary heart disease. Among them, nicotine acts on the sympathetic nervous system, making the heart beat faster and blood pressure higher; in addition, it also promotes platelet adhesion and increased fibrin content, which facilitates the formation of blood clots, thus blocking small arteries. Another major component, carbon monoxide, can lead to arterial wall hypoxia, making the arterial wall edema, promoting lipid infiltration and deposition, and promoting atherosclerosis. Particularly serious is that smoking can induce coronary artery spasm, which slows blood flow in the coronary arteries, reduces blood flow, and increases the viscosity of blood, leading to myocardial hypoxia and even causing myocardial infarction. In addition, smoking can also cause a significant increase in the morbidity and mortality of patients with coronary heart disease, while quitting smoking can significantly reduce the morbidity and mortality of coronary heart disease. Therefore, smoking is the main risk factor for coronary heart disease.