Tobacco is an annually-grown herbaceous plant. It is found in cultivation, where it is the most commonly grown of all plants in the genus Nicotiana
, and its leaves are commercially grown in many countries to be processed into tobacco. It grows to heights between 1 and 2 meters (3' to 6'). Research is ongoing into its ancestry among wild Nicotiana species, but it is believed to be a hybrid of Nicotiana sylvestris, Nicotiana tomentosiformis, and possibly Nicotiana otophora.
Tobacco is a is a robust annual little branched herb up to 2.5 m tall with large green leaves and long trumpet-shaped white-pinkish flowers. All parts are sticky, covered with short sticky-glandular hairs, which exude a yellow secretion containing nicotine. Flowers are borne in branch-end many-flowered clusters. Flower tube is 5-6 cm long, 5 mm in diameter, expanded in the lower third and upper third, petals broadly triangular, white-pinkish with pale violet or carmine colored tips tube yellowish white. Calyx is with five narrowly triangular sepals which are 1.5-2 cm long. Leves are varied in size, the lower leaves are the largest at up to 60 cm long, short-stalked or unstalked, oblonged-elliptic, shortly tapering at the tip, decurrent at the base, the upper one stalkless and smallest, oblong-lanceshaped or elliptic. Fruit is capsular ovoid or ellipsoid, surrounded by the persistent calyx and with a short apical beak, about 2 cm long. Seeds are very numerous, very small, ovoid or kidney shaped, brown. Tobacco is a native of tropical and subtropical America but it is now commercially cultivated worldwide.
Tobacco has a long history of use by medical herbalists as a relaxant, though since it is a highly additive drug it is seldom employed internally or externally at present. The plant should be used with great caution. when taken internally it is an addictive narcotic. The active ingredients can also be absorbed through the skin.
The leaves are antispasmodic, discutient, diuretic, emetic, expectorant, irritant, narcotic, sedative and sialagogue. Traditionally, the leaf has been taken internally as a cholagogue to calm the liver. They are used externally in the treatment of rheumatic swelling, skin diseases and scorpion stings. Wet tobacco leaves can be applied to stings in order to relieve the pain. They are also a certain cure for painful piles. A poultice of the leaves has been used to treat headaches. The juice of green tobacco has been used as an eyewash. The leaves are mixed with the stem and leaves of Rhabdadenia biflora to remedy the wound of stingrays.