At one time the Henbane was held in great esteem as a medicinal plant, and was then to be found very commonly on rubbish heaps, and the banks of ditches. Although it is still retained in the Pharmacopoeia, its empirical use is not so great as formerly, neither does the plant appear to be so plentiful as of old. Its appearance and smell are somehow suggestive of its evil nature. It has a stout, branching stem, growing to a height of about two feet. The leaves are oblong, with irregular lobes, and the bases of the upper ones clasp the stem. The flowers spring from the axils of the leaves, and are almost stalkless. The calyx is pitcher-shaped, with a five-toothed mouth. The corolla is funnel-shaped, with five unequal lobes, and of a dingy yellow, streaked with purple-brown veins, though a form occurs with the corolla uniformly yellow. The five stamens are inserted at the base of the corolla-tube, and end in purple anthers, discharging their pollen by slits. The ovary is two-celled, supporting a simple style with a round head—the stigma. The whole plant is densely covered with sticky hairs.

On fertilization the ovary grows into a constricted capsule, with a distinct lid, which drops off to release the numerous seeds. It is the only British representative of the genus, which is said to get its name from two Greek words, Us, a hog, and Kuamos, a bean, but such etymology cannot be considered at all satisfactory. It flowers from June to August.