Bloodletting (blood withdrawal), 1500 BC – A misunderstanding lasting thousands of years

The practice of bloodletting—taking blood from a patient to treat or prevent disease—has been largely ineffective or harmful. Nevertheless, it was one of the most common medical practices performed by physicians for more than 2000 years. For example, an illustration from an ancient Egyptian tomb (around 1500 BC) shows leeches being used to draw blood. Moreover, bloodletting had an extremely wide geographical distribution and was practiced by the ancient Mesopotamians, Egyptians, Greeks, Mayans and Aztecs, and inhabitants of the Indian Subcontinent (for example, ancient Ayurvedic medicine). Early Islamic medical writers recommended the practice, and the Talmud, one of the Jewish sacred books, recommended certain days of the week and month for bloodletting.

Bloodletting became increasingly popular after the time of the Greek physician Galen, who agreed with Hippocrates's ideas that diseases arose from an imbalance of four humors (fluids). These four humors are blood, black bile, yellow bile and phlegm. Galen made complex recommendations, emphasizing that circumstances such as the patient's age, the weather, and signs and symptoms were related to the amount of blood to be withdrawn. During the Middle Ages and Renaissance, European barber-surgeons enthusiastically performed bloodletting, and physicians continued to bleed patients for every conceivable ailment. Large amounts of blood were drained from President George Washington because of a throat infection, and this hastened his death. Bloodletting continued into the twentieth century and was even recommended by Canadian physician William Osler in the 1923 edition of his textbook on medical practice.

Bloodletting was carried out using lancets (thin blades), scarificators (spring-loaded devices with multiple blades) and leeches. Perhaps bloodletting remained popular over centuries in which patients had very few viable treatments because of a placebo effect. Today, bloodletting/blood withdrawal (therapeutic phlebotomy) has very few clinical uses except, for example, in patients with hemochromatosis to reduce high iron levels in the blood or polycythemia, a disease characterized by an excess of red blood cells. In 2010, the California Department of Consumer Affairs banned the Chinese practice of bloodletting, which was common among licensed acupuncturists.

Description of the article image: A medieval manuscript depicting bloodletting with a sharp instrument. European barber-surgeons in the Middle Ages and Renaissance enthusiastically practiced bloodletting, deceiving patients for every conceivable need.

Historical figures mentioned in the article: Galen of Pergamon (129–199), George Washington (1732–1799), William Osler (1849–1919)

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