Tobacco is a plant that is native to the Americas. It is in the same family as potatoes, tomatoes, and chili peppers. The leaves of the tobacco plant are dried and then smoked, chewed, or sniffed.Tobacco contains nicotine, which is a addictive drug. Nicotine is also a poison, and it can be deadly in high doses. Tobacco use is the leading cause of preventable death in the United States. It causes more than 480,000 deaths each year.Smoking cigarettes is the most common way that people use tobacco. Cigarette smoking increases the risk of lung cancer, heart disease, and other health problems.