Bane
Bane originally in English meant a form of nemesis, the bringer of ruin. Also an affliction, curse, evil, ill, plague, scourge or woe, in Old English 'bana' had a more specific and immediate meaning, of 'slayer', 'murderer.' Possibly derived from Nordic languages brought to Britain by the Vikings, where 'bane' (in Swedish for example) means 'something causing your death'. From which Bane, is also a disease in sheep, commonly termed 'the rot'.
Specific plants were also considered bane. In the Middle Ages, plants of the genus Aconitum, were known to have prophylactic or poisonous properties, such as henbane, leopard's bane, wolfsbane, and aconite. Wolfsbane was believed to ward of potential werewolves, and leopard's bane to ward off leopards. In 1910, an American homeopathic doctor living in London, Hawley Harvey Crippen, allegedly used scopolamine, an alkaloid extracted from henbane, to poison his wife. Henbane is also thought to have been the 'hebenon' poured into the ear of Hamlet's father.