The species is native to Europe, North Africa, and Western Asia, and has become naturalized in parts of North America. In areas where it has become naturalized it can often be found in shady, moist areas with a limestone-rich soil. The name bella donna is derived from Italian and means "beautiful woman"; it was once used by women to enlarge the pupils of their eyes.
Atropa belladonna is a branching herbaceous perennial, often growing as a subshrub, from a fleshy rootstock. Plants grow to 1.5 m (5 ft) tall with 18 cm (7 in) long ovate leaves. The bell-shaped flowers are dull purple with green tinges and faintly scented. The fruits are berries that are green, approximately 1 cm in diameter and when ripe, turn black with a shiny sheen. The berries are sweet and are consumed by animals that disperse the seeds in their droppings, even though the seeds contain toxic alkaloids. There is a pale yellow flowering form called Atropa belladonna var. lutea with pale yellow fruit.
Atropa belladona is rarely used in gardens, but when grown it is usually for its large upright habit and showy berries. It is considered a weed species in parts of the world, where it colonizes areas with disturbed soils. Germination of the small seeds is often difficult, due to hard seed coats that cause seed dormancy. Germination takes several weeks under alternating temperature conditions but can be sped up with the use of gibberellic acid. The seedlings need sterile soil to prevent damping off and resent root disturbance during transplanting.
The first botanical description was by Linnaeus in Species Plantarum in 1753. It is in the nightshade family (Solanaceae), which it shares with potatoes, tomatoes, eggplants, jimsonweed, tobacco, wolfberry, and chili peppers. The common names for this species include belladonna, deadly nightshade, dwale, banewort, devil's cherries, naughty man's cherries, divale, black cherry, devil's herb, great morel, and dwayberry. It is one of two species to be known as deadly nightshade, the other is Solanum nigrum.
The name Atropa is thought to be derived from that of the Greek goddess Atropos, one of the three fates or destinies that would determine the course of a man's life by the weaving of threads that symbolized their birth, events in that life and finally their death; with Atropos cutting these threads to mark the latter.
Belladonna is one of the most toxic plants found in the Western hemisphere. All parts of the plant contain tropane alkaloids. The berries pose the greatest danger to children because they look attractive and have a somewhat sweet taste. The consumption of two to five berries by children and ten to twenty berries by adults can be lethal. The root of the plant is generally the most toxic part, though this can vary from one specimen to another. Ingestion of a single leaf of the plant can be fatal to an adult.
The active agents in Belladonna, atropine, hyoscine (scopolamine), and hyoscyamine, have anticholinergic properties. The symptoms of belladonna poisoning include dilated pupils, sensitivity to light, blurred vision, tachycardia, loss of balance, staggering, headache, rash, flushing, dry mouth and throat, slurred speech, urinary retention, constipation, confusion, hallucinations, delirium, and convulsions. The plant's deadly symptoms are caused by atropine's disruption of the parasympathetic nervous system's ability to regulate non-volitional/subconscious activities such as sweating, breathing, and heart rate. The antidote for belladonna poisoning is physostigmine or pilocarpine, the same as for atropine. Atropa belladonna is also toxic to many domestic animals, causing narcosis and paralysis. However, cattle and rabbits seem to eat the plant without suffering harmful effects.
The common name belladonna originates from its historic use by women - Bella Donna is Italian for beautiful lady. Drops prepared from the belladonna plant were used to dilate women's pupils, an effect considered attractive. Today it is known that the atropine in belladonna acts as an antimuscarinic, blocking receptors in the muscles of the eye that constrict pupil size. Belladonna is currently rarely used cosmetically, as it carries the adverse effects of causing minor visual distortions, inability to focus on near objects, and increased heart rate. Prolonged usage was reputed to cause blindness.
There is currently insufficient scientific evidence to recommend the use of belladonna for any condition, although some of its components have accepted medical uses. The alkaloid l-atropine was purified from belladona in the 1830s, enabling studies of the autonomic nervous system leading to the recognition of the function of the neurotransmitter acetylcholine. Atropine reverses the effects of poisoning by organophosphate nerve agents used for chemical warfare. . Atropine is also widely used as a cardiac medication to increase the heart rate of patients suffering from bradycardia.
Donnatal, a prescription pharmaceutical approved in the United States by the FDA to "provide peripheral anticholinergic/antispasmodic action and mild sedation", is a phenobarbital formulation also containing alkaloids derived from belladonna. It is also labeled as not being tested for effectiveness in the treatment of irritable bowel syndrome and acute enterocolitis and as an adjunctive therapy in the treatment of duodenal ulcers.
A. belladonna has been used in traditional treatments for centuries for an assortment of conditions including headache, menstrual symptoms, peptic ulcer disease, histaminic reaction, inflammation, and motion sickness. Homeopathic preparations with the name belladonna have been sold as treatments for various conditions.
Atropa belladonna, along with related plants such as jimson weed, has occasionally been used as a recreational drug because of the vivid hallucinations and delirium that it produces. These hallucinations are most commonly described as very unpleasant, however, and recreational use is considered extremely dangerous because of the high risk of unintentional fatal overdose. In addition, the central nervous system effects of atropine include memory disruption, which may lead to severe confusion.
In the past, it was believed that witches used a mixture of belladonna, opium poppy, and other plants, typically poisonous (such as monkshood and poison hemlock) in flying ointment they applied to help them fly to gatherings with other witches. Carlo Ginzburg and others have argued that flying ointments were preparations meant to encourage hallucinatory dreaming; a possible explanation for the inclusion of belladonna and opium poppy in flying ointments concerns the known antagonism between tropane alkaloids of belladonna (specifically scopolamine) and opiate alkaloids in Papaver somniferum (specifically morphine), which produces a dream-like waking state. This antagonism was known in folk medicine, discussed in eclectic (botanical) medicine formularies, and posited as the explanation of how flying ointments might have actually worked in contemporary writing on witchcraft. The antagonism between opiates and tropanes is the original basis of the Twilight Sleep that was provided to Queen Victoria to deaden pain as well as consciousness during childbirth, and which was later modified so that isolated alkaloids were used instead of plant materials, the whole belladonna herb especially being notable for its unpredictability of effect and toxicity.