Nicotiana is a genus of herbaceous plants and shrubs in the family Solanaceae, that is indigenous to the Americas, Australia, Southwestern Africa and the South Pacific. Various Nicotiana species, commonly referred to as tobacco plants, are cultivated as ornamental garden plants. N. tabacum is grown worldwide for the cultivation of tobacco leaves used for manufacturing and producing tobacco products, including cigars, cigarillos, cigarettes, chewing tobacco, dipping tobacco, snuff, and snus.

The Solanaceae, or the nightshades, are a family of flowering plants that ranges from annual and perennial herbs to vines, lianas, epiphytes, shrubs, and trees, and includes a number of agricultural crops, medicinal plants, spices, weeds, and ornamentals. Many members of the family contain potent alkaloids, and some are highly toxic, but many—including tomatoes, potatoes, eggplant, bell and chili peppers—are used as food. The family belongs to the order Solanales, in the asterid group and class Magnoliopsida (dicotyledons). The Solanaceae consists of about 98 genera and some 2,700 species, with a great diversity of habitats, morphology and ecology.