Hyoscyamus niger, commonly known as henbane, black henbane or stinking nightshade, is a poisonous plant in the family Solanaceae that originated in Eurasia, though it is now globally distributed.
It was historically used in combination with other plants, such as mandrake, deadly nightshade, and datura as an anaesthetic potion, as well as for its psychoactive properties in "magic brews". These psychoactive properties include visual hallucinations and a sensation of flight. It was originally used in continental Europe, Asia, and the Arab world, though it did spread to England in the Middle Ages. The use of henbane by the ancient Greeks was documented by Pliny who said it was "of the nature of wine and therefore offensive to the understanding," and by Dioscorides who recommended it as a sedative and analgesic. The plant, recorded as Herba Apollinaris, was used to yield oracles by the priestesses of Apollo. Recently evidence for its earlier use in the Scottish Neolithic has been debated.John Gerard's Herball states: "The leaves, the seeds and the juice, when taken internally cause an unquiet sleep, like unto the sleep of drunkenness, which continueth long and is deadly to the patient. To wash the feet in a decoction of Henbane, as also the often smelling of the flowers causeth sleep."
The name henbane dates at least to AD 1265. The origins of the word are unclear, but "hen" probably originally meant death rather than referring to chickens.Hyoscyamine, scopolamine, and other tropane alkaloids have been found in the foliage and seeds of the plant. Common effects of henbane ingestion in humans include hallucinations, dilated pupils, restlessness, and flushed skin. Less common symptoms, such as tachycardia, convulsions, vomiting, hypertension, hyperpyrexia, and ataxia, have all been noted.
Henbane can be toxic, even fatal, to animals in low doses. Not all animals are susceptible; for example, the larvae of some Lepidoptera species, including cabbage moths, eat henbane.
It was sometimes one of the ingredients in gruit, traditionally used in beers as a flavouring. Several cities, most notable Pilsen, were named after its German name form "Bilsenkraut" in context of the production for beer flavouring. It fell out of usage for beer when it was replaced by hops in the 11th to 16th centuries, as the Bavarian Purity Law of 1516 outlawed ingredients other than barley, hops, yeast, and water.
Henbane is sometimes identified with the "hebenon" poured into the ear of Hamlet's father, although other candidates for hebenon exist.
In 2008, celebrity chef Antony Worrall Thompson recommended henbane as a "tasty addition to salads" in the August 2008 issue of Healthy and Organic Living magazine. He subsequently said he had made an error, confusing the herb with fat hen, a member of the spinach family. He apologized, and the magazine sent subscribers an urgent message stating, "[henbane] is a very toxic plant and should never be eaten".