Plant 94

Atropa belladonna L. (Solanaceae)


Deadly nightshade

Deadly nightshade is a herbaceous perennial in the potato family. It is native to calcareous soils in Britain and across Europe, although it has a much wider distribution because of plant by humans. Deadly nightshade's native habitat is the understory of woodlands and marginal habitats, such as hedgerows and near walls. The plant's purple flowers eventually develop into distinctive, shiny, black berries.

The name Atropa commemorates the last of the three Moirai, or Fates, of Greek mythology, who 'cut the thread of life'. All parts of the plant are extremely poisonous to humans because of the presence of tropane alkaloids, including hyoscyamine and hyoscine. These alkaloids are also found in other solanaceous genera such as Hyoscyamus (henbane), Mandragora (mandrake) and Datura (thorn apple). These substances interfere with the function of the parasympathetic nervous system, disrupting involuntary bodily processes. Despite its extreme toxicity, deaths from accidental nightshade poisoning are rare. Some animals appear unaffected by the toxins, perhaps explaining the plant's effective seed distribution. The presence of significant quantities of atropine in meat and honey have been reported to produce secondary poisoning in humans. Physostigmine, extracted from the Calabar bean (Physostigma venenosum), can be an effective antidote.

Plants producing tropane alkaloids have historical associations with murder through poisoning. Atropa was used to murder several Roman Emperors. Eleventh-century Scots used Atropa to poison invading Anglo-Saxons, whilst it was used in a Scottish case of attempted murder in 1994. The alkaloids also have strong associations with the history of European witchcraft. Atropa is frequently suggested as one of the ingredients of 'flying ointment', a hallucinogenic preparation giving its users a vivid sensation of flight, frenzied dancing and communication with other worlds. Deadly nightshade certainly produces hallucinations, although the threshold between hallucinogenic and life-threatening doses is very slight.

As with many extremely poisonous plants, useful medicinal extracts have been isolated from Atropa, including the tropane alkaloid atropine. Atropine is used to regulate heart rate and as an antidote for poisoning by organophosphates and nerve agents, such as sarin. The United States Army even provides its soldiers who are at risk from chemical weapon attacks with self-medication kits containing atropine sulphate. Most famously, atropine dilate the pupil of the eyes; during the European Renaissance it was used cosmetically, and apparently gives rise to the specific epithet belladonna (beautiful lady). During the nineteenth century, the use of Atropa in some medical preparations led to inadvertent poisoning.

Further reading

Lee M 2007. Atropa belladonnaJournal of the Royal College of Physicians Edinburgh 37: 77-84.

Mann J 1994. Murder, magic and medicine. Oxford University Press.

James Penny