The Biology Book: From the Origin of Life to Epigenetics, 250 Milestones in the History of Biology (2015)

Four Humors

Hippocrates (c. 460–c. 370 BCE), Galen (c. 130–c. 200), Avicenna (980–1037)

c. 400 BCE

For over two millennia, both Eastern and Western medical practitioners subscribed to the belief that a balance of four bodily humors (“fluids”) affected our physical and mental well-being. The concept of the four humors originated in ancient Egypt and Mesopotamia, and was systematized and adapted to the practice of medicine—humorism—by Hippocrates during the fourth century BCE. Good health resulted when these fluids—blood, phlegm, black bile, and yellow bile—were in balance, while their excess or deficiency resulted in sickness.

This notion displaced the prevailing ancient belief that attributed diseases to supernatural evil spirits. Humorism gained ready acceptance over the centuries and was embraced as the basis for medical treatment by the Greeks and Romans, as promoted by Galen. He also proposed that humor excesses were responsible for such temperamental traits as being sanguine (blood), phlegmatic (phlegm), melancholy (black bile), and choleric (yellow bile). From the ancient world, it spread over the centuries, with local modifications, to the Muslims, to China and India, and Western European physicians. In The Canon of Medicine (1025), the famed Muslim physician Avicenna expanded upon the relationship between this imbalance to changes in temperament and disease and proposed its association with the master organs—the brain and heart. During the Elizabethan period, to maintain a balance in the fluids, which were believed to be produced by and circulating in the body, adjustments were made in the diet, exercise, clothing, and even bathing habits; bathing was perceived to be more harmful for men than women.

“Heroic medicine,” as practiced by Western European-trained physicians, sought to restore this balance in humors by employing such drastic approaches as purging, inducing vomiting, and bleeding; George Washington’s death in 1799 is generally believed to have been inadvertently hastened when his physicians bled him of ~125 ounces, or half, his total blood volume. Less dramatic treatment approaches involved the application of heat, cold, moisture, or dryness. Humorism continued to dominate thinking on well-being and the practice of medicine until the nineteenth century, when modern theories of medicine, based on advances in cellular pathology and biological and bacterial causes of disease, had gained acceptance.

SEE ALSO: Scientific Method (1620), Cell Theory (1838), Germ Theory of Disease (1890).

In ancient times, melancholy was attributed to an overabundance of the “black bile” humor, and the planets were believed to be able to correct the balance of humors. This stained glass, from the southern Netherlands (c. 1530), is entitled “The Planet Saturn Driving Out a Monk with a Pig’s Head, or Time Banishing Melancholy.”