Tobacco

Tobacco is an agricultural product processed from the fresh leaves of plants in the genus Nicotiana. It is most commonly smoked in the form of cigarettes or cigars. Tobacco has been growing on both American continents since about 6000 BC and was used by native cultures by around 3000 BC. It has been smoked, in one form or another, since about 3000 BC. Tobacco has a long history of use in Native American culture, and played an important role in the political, economic, and cultural history of the United States of America.

Dried, cured, and unprocessed tobacco is commercially available all over the world. Smoke from burning, or otherwise heated, tobacco can be inhaled in the forms of cigarettes, cigars, stem pipes, water pipes, and hookahs. Tobacco can also be chewed, dipped (placed between the cheek and gum), or sniffed into the nose as finely powdered snuff. Many countries set minimum legal smoking ages, regulating the purchase and use of tobacco products. Bhutan is the only country in the world where tobacco sales are illegal. According to the World Health Organization, tobacco smoke is the second biggest cause of death worldwide, and is reported to have been responsible for the deaths of 100 million people in the 20th century.

All methods of tobacco consumption result in varying quantities of nicotine being absorbed into the user's bloodstream. Over time, tolerance and dependence develop. Absorption quantity, frequency, and speed of tobacco consumption are believed to be directly related to biological strength of nicotine dependence, addiction, and tolerance.