The use of the word tobacco is generally accepted as referring to the products of the tabacum species and so it will be in what follows. It is the most widely grown commercial non-food plant in the world. It holds a high importance in financial and economic policies in many countries. Consumption is by way of smoking, inhaling or chewing and is a habit forming narcotic, and although bans of it's use have been attempted, it's consumption marches steadily forward. Originally having religious significance, subsequent claims of medicinal benefit have alternated with accusations of a positive danger to health.
Tobacco is grown with assistance of man with the leaf as the only valuable part of the plant.
Tobacco growth is restricted, by environmental factors, to about the latitudes of 60 degrees north to 45 degrees south, with the majority of the tobacco entering the world trade produced in the latitudes between 45 degrees north and 30 degrees south. Limits to it's growth are figured by the number of frost free days. Almost all continents are capable of growing tobacco but the United States, China, India and Brazil are the leading countries to grow tobacco. The majority are confined to South America and this, with other geographical evidence suggests a South American origin for this genus. N. tabacum has a uniquely high proportion of alkaloids occurring as nicotine and is considered to have survived as a species by man's protection.