Harmful Components of Tobacco Smoke During the combustion process of tobacco, more than 4,000 known chemical substances can be produced, of which 69 are carcinogenic or cancer-promoting substances. The main harmful substances in tobacco smoke are: 1, nicotine: also known as nicotine, is a highly addictive substance, its addictiveness is second only to heroin. Nicotine can act on the brain of smokers, making smokers dependent on tobacco, which is the main ingredient leading to tobacco addiction. Xing Guohong, Department of Respiratory Medicine, Jinan General Hospital, Jinan Military Region 2, cigarette tar: commonly known as “cigarette oil”, each cigarette contains 5-15 milligrams, containing a variety of carcinogenic substances. It can adhere to the mucous membrane of the airways and alveoli, affecting its function, and can cause cancer in the long run, which is the main cause of lung cancer and laryngeal cancer. Tar is also the cause of yellowing of smokers’ teeth and fingers. 3. Carbon monoxide: it is a colorless and tasteless gas that can produce 20-30 ml per cigarette. Its affinity for hemoglobin is 260 times higher than that of oxygen, which will destroy the function of the blood to transport oxygen, thus affecting the whole body organ function and metabolism. In winter, when doors and windows are closed, smoking 1 cigarette can make myself and the whole family blood carbon hemoglobin rise 7 times and 6 times respectively. Carbon monoxide can increase cholesterol stores and accelerate atherosclerosis. Carbon monoxide and smoke in the nitric oxide, gas-phase free radicals and other substances, but also can damage the endothelial function of the blood vessels, increase blood viscosity, promote thrombosis, increase oxidative stress and inflammation, induced or exacerbated cardiovascular disease. 4, a variety of toxic compounds: such as benzo(a)pyrene, formaldehyde, hydrocyanic acid, acrolein and other toxic substances, can seriously damage the bronchial mucosa, so that the bronchial tubes and lungs become infected. Benzo(a)pyrene and formaldehyde are strong carcinogens. 5, radioactive substances: tobacco planting in the application of uranium-containing phosphate fertilizer, uranium in tobacco can be decomposed polonium, lead, radium, radon and other radioactive isotopes. When smoking, these isotopes can be inhaled into the lungs and deposited in the body, these rays not only on the lungs, but also on the liver, kidney damage, is an important carcinogen. 6, harmful metals: tobacco contains cadmium, mercury, lead, arsenic, nickel and other harmful metals, such as cadmium is a strong carcinogen, and can cause respiratory asthma, emphysema; into the reproductive system, can kill sperm, causing male infertility; into the skeleton, can cause decalcification of bones, deformation, brittle, and very easy to fracture. 7, other harmful substances: acetone (paint stripper), ammonia, organophosphorus, nitrosamines, naphthalene and so on.