A plant with leaves that have high levels of the addictive chemical nicotine. After harvesting, tobacco leaves are cured, aged, and processed in various ways. The resulting products may be smoked (in cigarettes, cigars, and pipes), applied to the gums (as dipping and chewing tobacco), or inhaled (as snuff). Cured tobacco leaves and the products made from them contain many cancer-causing chemicals, and tobacco use and exposure to secondhand tobacco smoke have been strongly linked to many types of cancer and other diseases. The scientific name of the most common tobacco plant is Nicotiana tabacum.