Hyoscyamus is a genus, or related group, of 11 species of flowering plants belonging to the nightshade family. Hyoscyamus species are commonly known as henbane. Some species have medicinal or therapeutic properties as well as being highly toxic. Hyoscyamus species are surrounded by legends and myths dating back many centuries, and the plants were often associated with witchcraft.
Hyoscyamus has been used throughout history to cure a variety of ailments. Records indicate that ancient Egyptians smoked dried henbane to cure toothache. Ointments were often used to treat localized aches and pains, and tinctures were given to women in labor to reduce pain and to render the patient insensitive to pain. Poultices including the leaves of hyoscyamus species were used as dressings for open wounds and ulcers.
The properties of the hyoscyamus species are used in the early treatment of Parkinson's disease, because the plant, when prepared appropriately, has an anti-spasmodic effect and, in the early stages of Parkinson's disease, can reduce tremors and rigidity. Hyoscyamus has also commonly been used to soothe asthma and incessant coughing. The treatment included mixing the plant with several other herbs and smoking the result, which would relax the muscles of the respiratory system.
Hyoscyamus plants have psychotropic properties, meaning the plants can effect or alter perception. These plants are capable of causing hallucinations and desensitization, and these psychoactive properties were still used by some in the early 21st century to treat mental health problems, especially those involving panic, anxiety and compulsive behavior. Herbalists also still provide hyoscyamus remedies, but it should be noted that, because of the plants' toxicity, henbane and hyoscyamus preparations should only be taken on the advice of a reputable supplier, and the plants should never be handled or used in herbal remedies by anyone other than an experienced herbalist.
Symptoms of hyoscyamus poisoning or over-dosing can include restlessness, hallucinations, desensitization and a feeling of unreality, delirium and dysphasia, or difficulty swallowing. Potentially life-threatening effects can include tachycardia, which is a dangerously rapid heartbeat usually in excess of 100 beats per minute; and hyoscyamus, which can induce comas. There have been reported incidents of death, particularly in children, from ingesting the seeds of these plants.
Hyoscyamus varieties include Egyptian henbane, white henbane, black henbane and golden henbane. The flowers generally have a distinctive and offensive odor and are often known as stinking nightshade. The foliage of the hyoscyamus species are covered with sticky hairs. Egyptian henbane is one of the most potent varieties.