Medicinal plant. Close up of the Henbane flower Hyoscyamus niger (Solanceae family). Henbane is one of the most poisonous plants in Europe. The flowers are bell shaped and yellow with purple veining, and are surrounded by pilose (hairy) leaves. Henbane is typically found growing on wasteground or at roadsides. Henbane contains a mixture of alkaloids including scopolamine (hyoscine), hyoscyamine and atropine. These drugs are mainly used as analgesics (painkillers),muscle relaxants and myadriatics (drugs which dilate the pupils). Henbane is rare and cases of poisoning are unusual. Henbane is also a sedative and has been used as a toothache remedy.