Tobacco is a baked product from the leaves of tobacco plants. The plant is part of the family Nicotiana and Solanaceae (Solanaceae). Although more than 70 kinds of tobacco are known, the main commercial crop is tobacco. A more efficient variant, N. rustica, is also used around the world.

Tobacco contains an alkaloid nicotine (a stimulant) and a harmful alkaloid. Dry tobacco is mainly used for smoking in cigarettes, cigars, pipe cigarettes and flavored hookah. They can also be used as snuff, chewing tobacco, dipping tobacco and snuff.

Tobacco use is a risk factor for many diseases, especially those affecting the heart, liver and lungs, and many cancers. In 2008, the World Health Organization ranked tobacco as the world's largest preventable single cause of death.