Alkaloid ("Agonopterix alstroemeriana)." This moth feeds on its highly toxic and alkaloid-rich host plant poison hemlock ("Conium maculatum") during its larval stage. "A. asltroemeriana" may benefit twofold from the toxicity of the naturally-occurring alkaloids, both through the unpalatability of the species to predators and through the ability of "A. alstroemeriana" to recognize "Conium maculatum" as the correct location for oviposition. Medical use of alkaloid-containing plants has a long history, and, thus, when the first alkaloids were isolated in the 19th century, they immediately found application in clinical practice. Many alkaloids are still used in medicine, usually in the form of salts,
Poison "gu" poison. Poison was also employed in gunpowder warfare. For example, the 14th-century Chinese text of the "Huolongjing" written by Jiao Yu outlined the use of a poisonous gunpowder mixture to fill cast iron grenade bombs. The term "poison" is also used in a figurative sense. The "[s]lang sense of "alcoholic drink" [is] first attested 1805, American English." (e.g., a bartender might ask a customer "what's your poison?") Figurative use of the term dates from the late 15th century. Figuratively referring to persons as poison dates from 1910. The figurative term "poison-pen letter" became well known in "...1913 by a