The prepared leaves of the Old Earth tobacco plant Nicotiniana tabacam, used by Terragen mammals as a drug. The active substance is nicotine, a cholinergic agonist with mild mood and cognition enhancing effects and strong addiction potential. The drug is commonly smoked or chewed.
Tobacco was originally used by the humans local to South America, though the use spread worldwide on Old Earth during the Industrial Age. Tobacco production became a major industry, but due to health concerns and the Information Age anti-drug movement also increasingly controversial. During the middle first and early second century AT (21st century c.e.) more and more extensive bans were instituted, supported by major international organisations, governments and pharmaceutical companies. An unintended effect of these bans, especially the infamous EU ban of 91-130 AT (2060-2099 c.e.) was the growth of tobacco mafias, illegal organisations exploiting the relatively mild punishments for tobacco smuggling, the intense demand and the growing influence of the smoking associations. The tobacco mafias were often based in libertarian enclaves and contributed sizeable income.
While the tobacco bans were implemented, the legacy of industrial-era harsh legislation against mild psychoactive drugs was finally abolished in most polities. Ironically many of the liberal forces pushing soft drug legalisation also strongly promoted tobacco prohibition; it took a generation shift to accept that the methods that did not work for one problem did not work for the other. The legalisation destroyed the huge profits of tobacco smuggling. Competition from other drugs, effective neuropsychological addiction treatments and climate change made tobacco diminish in importance.
Tobacco smoking never caught on off-world, due to the inherent problems of smoking in confined space habitats. The exception was the cislunar colonies, where tobacco chewing and intravenous use was endemic. The tobacco plant was instead a favorite gengineering object for food or other drug production, resulting in the wide variety of space crops today called baccas.
Tobacco remains sparsely used in the post-Expulsion world, mainly due to its traditional importance as one of the "20 natural drugs" from Old Earth. It is used in religious and historical ceremonies, as an incense or symbolic drug. Various enhanced variants have been developed and remain of local importance.