Smoking is harmful to health, and the World Health Organization requires smoking cessation and alcohol restriction. Smoking contains many toxic substances, such as coal tar and benzopyrene, which can damage the endothelium of human blood vessels and lead to cholesterol deposition in the endothelium, which can easily form arterial plaques, which may lead to brain infarction if the plaques fall off. Smoking can lead to cancer, such as nasopharyngeal and lung cancer, and the relationship between smoking and lung cancer in particular has been confirmed in numerous animal tests and clinical trials.