"Health effects of smoking" and "Dangers of smoking" redirect here. For cannabis, see Effects of cannabis. For smoking crack cocaine, see Crack cocaine § Health issues. Smoking can damage many parts of the body.Tobacco use has predominantly negative effects on human health and concern about health effects of tobacco has a long history. Research has focused primarily on cigarette tobacco smoking.Tobacco smoke contains more than 70 chemicals that cause cancer. Tobacco also contains nicotine, which is a highly addictive psychoactive drug. When tobacco is smoked, nicotine causes physical and psychological dependency. Cigarettes sold in underdeveloped countries tend to have higher tar content, and are less likely to be filtered, potentially increasing vulnerability to tobacco smoking related disease in these regions.