Long-term smoking of e-cigarettes will affect the function of the respiratory system, increase the incidence of malignant tumors, induce cardiovascular and cerebrovascular diseases, abnormalities in reproductive development, diabetes and other diseases. 1. Impact on respiratory system function: there is sufficient evidence that smoking can increase the incidence of chronic obstructive pulmonary disease (COPD). In addition, smoking can also lead to asthma in adolescents and increase the risk of tuberculosis and other respiratory tract infections. 2. Malignant tumors: Tobacco smoke contains a variety of known carcinogens, these carcinogens can make the normal growth control mechanism is dysfunctional, triggering mutations in key genes in the body, increasing the incidence of malignant tumors. 3. Cardiovascular and cerebrovascular diseases: Smoking damages the endothelium of blood vessels and narrows the lumen of arterial blood vessels, which can lead to the occurrence of atherosclerosis and trigger a variety of cardiovascular and cerebrovascular diseases. 4. Abnormal reproductive development: Smoking can lead to erectile dysfunction, spontaneous abortion and ectopic pregnancy. Smoking can also reduce the probability of conception, leading to placenta praevia, placental abruption, fetal growth restriction, low birth weight of newborns and sudden infant death syndrome. 5. Diabetes: There is evidence that smoking increases the incidence of type 2 diabetes and can increase the risk of complications. 6. Others: There is good evidence that smoking can cause periodontitis, cataracts, skin aging, dementia, etc. Smoking in people with Helicobacter pylori infection can lead to peptic ulcers. Smoking e-cigarettes has many hazards and it is recommended to quit smoking in time.