Bad blood

The origin of this well-known metaphor for ill feeling, animosity or antipathy between people has its roots in the ancient practice of bloodletting in the medicinal sense. Many ancient cultures believed in draining off bad or unhealthy blood and the practice continued for thousands of years into relatively modern times. It was known to the Mesopotamians and the Egyptians long before Greek medicine under Hippocrates and Galen adopted it. It was also independently known and practised in many other ancient cultures like those of India, China and Japan. In the Americas, it was practised by the Mayans and Aztecs. Hippocratic medicine, which influenced both European and Arabic medicine, was based on the four humours: blood (sanguine) black bile (melancholic) yellow bile (choleric) and phlegm (phlegmatic). Of these, the most important was blood because the four elemental concepts of earth, air, fire and water were thought to be present in blood. Bloodletting is still endemic to Arabic medicine and is mentioned in the Koran as follows. “The prophet Mohammed said, ‘how good the blood letter who relieves the person from bad blood.’” The practice continued throughout Europe during medieval times. In 17th century England, draining off bad blood was not only commonplace, but also had relevance to early psychology. Robert Burton (1577-1640), a scholar who was particularly interested in his own depressive moods, published a famous book The Anatomy of Melancholy in 1621. Burton wrote that people suffering from melancholia could be “full of bad blood, noxious humours” and that this may be eased by judicious bloodletting. Etymologically at least, Burton established a link between bad blood and mental states. From this time onwards, bad blood and ill blood were used interchangeably in the figurative sense of enmity between people, with ill blood finally dying out in favour of bad blood during the late 19th century. The Diary of Samuel Pepys, entry for 14 December 1663, states that the King’s ambassador in Paris, “hath received several affronts, and among others his harnesse cut, and his gentleman of horse killed, which will breed bad blood if true”. This is the first citation of bad blood in its modern figurative sense, missed or ignored by the OED, which gives 1755 as the first citation.