Nicotiana rustica, commonly known as Aztec tobacco or strong tobacco, is a rainforest plant in the family Solanaceae native to South America. It is a very potent variety of tobacco, containing up to nine times more nicotine than common species of Nicotiana such as Nicotiana tabacum. More specifically, N. rustica leaves have a nicotine content as high as 9%, whereas N. tabacum leaves contain about 1 to 3%. The high concentration of nicotine in its leaves makes it useful for producing pesticides, and it has a wide variety of uses specific to cultures around the world. However, N. rustica is no longer cultivated in North America, as N. tabacum has replaced it.

Nicotiana tabacum, or cultivated tobacco, is an annually grown herbaceous plant of the genus Nicotiana. N. tabacum is the most commonly grown species in the genus Nicotiana, as the plant's leaves are commercially harvested to be processed into tobacco for human use. The plant is tropical in origin, is commonly grown throughout the world, and is often found in cultivation. It grows to heights between 1 and 2 meters. Research is ongoing into its ancestry among wild Nicotiana species, but it is believed to be a hybrid of Nicotiana sylvestris, N. tomentosiformis, and possibly N. otophora.