In times gone by, human personalities were believed to be controlled by four humors: blood, phlegm, choler (yellow bile), and melancholy (black vile). Though this belief was long ago discredited, its influence lingers on in the English language. When "carminative" came into use in the 15th-century medical field, carminative agents were thought to be effective because they influenced the humors. The word comes from Latin "carrere," meaning "to card," referring to the act of cleansing or disentangling. This history reflects the theory that certain humors could be "combed out" like knots in wool.