The ancient doctrine that elemental body fluids or humours (blood, phlegm, yellow bile, and black bile) are the physiologic and pathologic basis of health and disease. Also called humorism, fluidism, humoralism.
Stressing the unity of the body and the strong interaction between mental and physical processes, humoral theory suggests that, provided one can discover the proper balance of humors within an individual, one can both restore the body to health and devise means of maintaining health for as long as possible. In humoralism, preventive and curative approaches are of equal relevance.