deadly nightshade Poisonous perennial plant native to Europe and w Asia. It has large leaves, purple flowers, and black berries. Alkaloids, such as atropine, are obtained from its roots and leaves. Eating the fruit can be fatal. Family Solanaceae; species Atropa belladonna.

dead·ly night·shade • n. a poisonous Eurasian plant (Atropa belladonna) of the nightshade family, with drooping purple flowers and black cherrylike fruit. Also called belladonna.