henbane or black henbane, herb ( Hyoscyamus niger ) native to the Mediterranean region and naturalized in parts of North America. It belongs to the family Solanaceae (nightshade family) and contains a narcotic poison (similar to that of the related belladonna) that is extracted from the leaves for medicinal use. The drug, also called henbane, is composed of alkaloids, chiefly hyoscyamine and scopolamine. Henbane is produced chiefly in Egypt, Russia, and Hungary; the United States is a major importer. The name henbane refers to the fact that the seeds of this herb are very poisonous to poultry. It is sometimes also called nightshade. Henbane is classified in the division Magnoliophyta, class Magnoliopsida, order Polemoniales, family Solanaceae.