Belladonna

Deadly nightshade is Atropa belladonna, and both parts of the name are worth reading. The genus honours Atropos, the eldest of the three Greek Fates, the one who cuts the thread of life, a botanist's frank acknowledgement that the plant kills. The species name, belladonna, beautiful woman, records the Renaissance cosmetic use of its juice to dilate the pupils, which was thought becoming; the active compound, atropine, still dilates the pupil in the eye clinic today. All parts of the plant are highly toxic, the glossy black berries most temptingly so, and it is among the most notoriously poisonous plants of Europe. This is stated as fact and warning, not as folklore.

Atropine's modern medical role goes well beyond the eye clinic use noted above: because it blocks the same nerve receptors that organophosphate nerve agents and pesticides overstimulate, atropine is the standard emergency antidote for that class of poisoning, carried in military and civilian auto-injectors precisely for this purpose, so a compound first isolated from a plant famous for killing is now issued specifically to save lives against a chemical threat unknown to the herbalists who first studied it. Deadly nightshade belongs to the family Solanaceae, the same botanical family as the tomato, potato, eggplant and chilli pepper, ordinary food crops that share its underlying chemistry closely enough that unripe green potatoes and nightshade-family foliage can themselves carry toxic alkaloids in smaller, usually non-lethal amounts.

Culpeper and the older herbalists place the nightshades under Saturn, the cold, heavy, malefic planet, which suits a plant of shadow and poison. Belladonna belongs, with henbane and datura, to the group of tropane-bearing nightshades associated with European witchcraft and the so-called flying ointments, salves compounded, in the trial literature and later reconstruction, from these plants, whose alkaloids produce delirium, dissociation and vivid sensations of flight. The connection between the witches' flight and the pharmacology of the nightshades is genuinely argued by historians, though how far the ointments were ever really used, as against being a fantasy of their prosecutors, remains uncertain. What is not uncertain is the plant's lethality.

Belladonna's toxicity produced a genuine modern regulatory episode: homeopathic teething products containing trace amounts of belladonna were pulled from the American market after the US Food and Drug Administration warned in 2016 and 2017 that some batches had been found with inconsistent, unsafely high amounts of the plant's alkaloids, a case in which the manufacturing process rather than any traditional use was at fault, and one that illustrates why the plant's warning label has never lost its relevance.