E-cigarettes may cause damage to the lungs, increase the incidence of chronic obstructive pulmonary disease (COPD), lung cancer and other related diseases or cause other lung injuries, which may also lead to the harm of other organs. 1. Increase the incidence of chronic obstructive pulmonary disease (COPD). E-cigarettes are mainly composed of nicotine, which is harmful to the lungs. Although the content of e-cigarettes may be smaller than that of real cigarettes, they can still damage the respiratory tract, and the long-term use of e-cigarettes will increase the incidence of COPD. 2. Lung cancer, the harmful substances in e-cigarettes are also carcinogenic to a certain extent, and year-round use may also lead to an increase in the incidence of lung cancer. 3. Causing other lung damage, e-cigarettes may also have other harmful particles in the formation of smoke, such as propylene glycol and other substances, inhaled into the lungs, some people may form a diffuse lung damage, resulting in coughing, chest tightness and other related symptoms. 4. Damage to other organs, such as long-term inhalation of nicotine may lead to increased incidence of cardiovascular diseases. To summarize, long-term use of e-cigarettes is also undesirable and can still cause harm to the human body.