During the Middle Ages, Monkshood was associated with witchcraft, and it has been used as an external painkiller in folk medicine ever since. The English name derives from the cowl-like shape of the flowers. It was used to poison enemy water supplies during times of war in ancient Europe and Asia. Hunters used its sap to poison spears, arrowheads & trap baits. In ancient Greek legends the plant originated from the saliva dripping from the fangs of Cerberus, the three-headed dog that  Eurystheus tasked Hercules to kidnap from the underworld.