Jimson weed or Jamestown weed, large, coarse annual plant (Datura stramonium) of the family Solanaceae (nightshade family), native to warm-temperate and tropical regions of the New World, but long widely distributed and often weedy. This and other species of the genus contain a narcotic poison, stramonium, similar to that of the related belladonna, that has been used by many peoples for various purposes, e.g., as a medicine (now chiefly inhaled for the relief of asthma or applied externally as a painkiller) and in the past as a poison and an instrument for obtaining prophetic dreams or messages in various tribes. The amusing antics of soldiers in colonial Virginia who ate Jimson weed have been recorded for history. Stramonium, comprised of several alkaloids (e.g., scopolamine, atropine, and hyoscyamine), may also be obtained from some other species of Datura. Scopolamine is used as a sedative. Jimson weed is classified in the division Magnoliophyta, class Magnoliopsida, order Polemoniales, family Solanaceae.