The theory of the four humors represents one of the longest-standing medical concepts in Western history, offering a framework for understanding human biology that persisted for over a millennium. This ancient system proposed that the human body was composed of four primary fluids, or humors. The state of a person’s health, temperament, and physical appearance was determined by the balance of these substances. Humoralism provided a comprehensive explanation for disease, personality, and the relationship between the body and the environment, dominating medical thought from antiquity through the Renaissance.
The Origin and Core Concept of Humoralism
The development of humoral theory is principally credited to ancient Greek physicians, notably Hippocrates, who began to define health and illness through a naturalistic rather than a supernatural lens. Hippocrates’ texts identified the specific bodily fluids—blood, phlegm, yellow bile, and black bile—as the components whose correct proportion maintained wellness. This idea was later expanded and systematized by Galen of Pergamon, whose writings cemented humoralism as the authoritative medical model for the Roman world and beyond. Galen connected these four bodily fluids to the four classical elements: earth, air, fire, and water. Each humor was also assigned a pair of qualities: hot or cold, and wet or dry.
The Four Specific Humors and Their Associations
Blood was associated with the element of air and the season of spring, defined by the qualities of being hot and wet. This humor was thought to be produced in the liver and was tied to a lively, sociable disposition.
Phlegm, a cold and wet humor, corresponded to the element of water and was dominant during the winter season. It was believed to originate in the brain and lungs, and an excess was associated with a calm, rational, and somewhat sluggish nature.
Yellow Bile, also known as choler, was characterized as hot and dry, linking it to the element of fire and the season of summer. This humor was believed to be secreted by the gallbladder and was associated with an easily angered, ambitious, and passionate personality.
Black Bile, or melancholy, was the cold and dry humor, corresponding to the element of earth and the season of autumn. This fluid was theoretically produced in the spleen, and its predominance was linked to a thoughtful, introspective, and often mournful temperament.
Understanding Health and Disease Through Balance
Health within the humoral system was defined as eucrasia, representing the balanced blend of the four humors. Disease, conversely, was understood as dyscrasia, an imbalance caused by an excess or deficiency of one or more bodily fluids. Physicians diagnosed illness by observing symptoms that indicated which humor was out of proportion, such as fever suggesting an excess of hot humors like blood or yellow bile.
To restore internal equilibrium, treatment methods focused on expelling the surplus humor or moderating the body’s qualities. These practices included:
- Dietary regulation and lifestyle changes prescribed to adjust the patient’s internal “heat” or “moisture.”
- Bloodletting used to draw off excess blood.
- Purging or emetics administered to remove excess bile or phlegm.
- Cupping, which involved applying heated glass cups to the skin to manipulate the circulation of the humors and alleviate localized imbalances.
The Cultural and Linguistic Legacy
The influence of the humors extended far beyond medical practice, forming the basis for a proto-psychological model of personality. The four temperaments—sanguine, phlegmatic, choleric, and melancholic—were directly named for the humor most dominant in an individual’s constitution. A person’s temperament was understood to dictate their character traits, emotional state, and behavioral tendencies.
Although the scientific basis of humoralism was abandoned, its language is still present in modern English. Phrases like “good humor” or “bad humor” refer to one’s mood or disposition, originating from the belief that fluid balance determined emotional state. The word “melancholy” remains a synonym for sadness, directly deriving from the name of the cold and dry humor. The theory declined as scientific discoveries, such as the understanding of the circulatory system and the advent of germ theory, provided more accurate explanations for disease and bodily function.