Normally, smoking is not allowed after coronary stent placement because the nicotine in tobacco causes the disease to worsen. Coronary stenting is generally used to treat coronary atherosclerotic heart disease, which is caused by the formation of atherosclerotic plaque in the coronary arteries leading to narrowing of the coronary arteries, which in turn causes myocardial ischemia. Atherosclerosis is formed when lipids are deposited in the damaged blood vessel walls following damage to the arterial lining, so any factor that causes damage to the blood vessels may exacerbate coronary heart disease. Nicotine in tobacco can damage the arterial lining, so it can cause or aggravate coronary heart disease. In addition, nicotine causes constriction of small blood vessels, leading to increased cardiac load and increased myocardial oxygen consumption, aggravating the condition. Therefore, patients placing arterial stents are not allowed to smoke and should strictly quit smoking to avoid aggravation of their condition.