A naturalistic medical system based on the idea that our bodies have four important fluids or humors--blood, phlegm, black bile, and yellow bile. Each humour is thought to have its own "complexion. " blood is hot and wet. Phlegm is cold and wet. Black bile is cold and dry. Yellow bile is hot and dry. These complexions have nothing to do with actual temperature and humidity. In addition to bodily fluids, three internal organs are considered highly important in humoral pathology. Each one has its own characteristic complexion. The heart is dry and cold. The brain is wet and cold. The liver is hot and wet. Specific forms of illnesses, medicines, foods, and most natural objects also have specific complexions. Curing an illness involves discovering the complexion imbalance and rectifying it.