An ancient theory stating that the body is composed of four basic humors such as black bile, yellow bile, phlegm, and blood that were used as a basis to determine the health of an individual. According to this theory, the four humors have to be in balance in order to be healthy. Otherwise, an excess or deficit on one of them results in disease or disability in the personality or physical health of an individual.
This theory was related and likened to the theory of the earth having four elements such as earth, fire, water and air in which balance in these elements allow for human life.
Also called: humoral theory, humorism, humoralism.