E-cigarettes have certain toxic effects on the human body. The principle of e-cigarettes is that nicotine and tar are heated electronically and then inhaled, which will reduce the damage to the alveoli, lung wall capillaries or lung mucosa and therefore reduce the incidence of lung cancer. But reducing the incidence of lung cancer does not mean that e-cigarettes are not toxic, usually the toxicity of e-cigarettes is heated tar composition for cardiovascular endothelial cells have a certain degree of damage and erosion, so especially for patients with coronary atherosclerotic heart disease or myocardial infarction in the past, not excessive smoking e-cigarettes, which can cause cardiovascular and even cerebrovascular poisoning.