Greeks and Romans, and the later Muslim and Western European medical establishments that adopted and adapted classical medical philosophy, believed that each of these humors would wax and wane in the body, depending on diet and activity.
Os grego e os romanos, e os establecementos médicos posteriores da Europa Occidental que adoptaban e adaptaban a filosofía médica clásica, crían que cada un deses humores poderían aumentar e diminuír no corpo, dependendo da dieta e da actividade.