The drug and also the plant known as the deadly nightshade, Atropa belladonna, which belongs to the nightshade family (Solanaceae). This is a coarse, perennial herb native to the Mediterranean regions of Europe and Asia Minor, but now grown extensively in the United States, Europe, and India. During the blooming period, the leaves, flowering tops, and roots are collected and dried for use. The plant contains several important medicinal alkaloids, the chief one being atropine, which is much used to dilate the pupils of the eye.