Why was the practice of Bloodletting thought to heal the sick in Ancient Europe and who discovered it?

Long after the rest of the world, the Ottomans, the Chinese, the Byzantines, had realized the finer points of anatomy and physiology, western Europe stayed stuck in an old paradigm they had learned from the ancient Greeks.

The practice of bloodletting was widespread, and had been practiced for over 2,000 years.

It went something like this: The body consisted of the four humours (fluids): blood, yellow bile, phlegm, and black bile. In order for the body, mind, and character to be healthy, these four fluids needed to be in perfect balance.

If something were wrong in the body or mind, something must be wrong with the humours.

The diagnosis? If someone were lecherous, warlike, and rash, they had a hefty presence of blood. If angry, violent, or vengeful, that could be attributed to an excess of yellow bile.

Cowardice, paleness, or dullness could be blamed on too much phlegm, and too much black bile was indicated by laziness, an overwrought disposition, or gluttony.

Common medical belief held that a good diet, exercise, and a good environment would keep the four humours in balance.

If they got out of wack, there were plenty of noninvasive remedies: laxatives or diuretics, hot baths with herbs, smoke from burning herbs, or in the case of injury, cauterization and sterilization of the wound.

For more serious situations, bloodletting was used. The reasoning behind the procedure was that if blood amounts were lowered, the other fluids would fall into balance. It was a crazy idea, and it didn’t work.

Bloodletting killed more people than it cured, yet it was performed on the sick well into the 19th century.

It’s believed that the practice of bloodletting has its origins in the earliest civilizations, including the Aztecs.