The Four Humours of Medieval Medicine

The theory lasted for many centuries

Hippocrates expounded a theory in the fourth century BC that outlasted the medieval era and dominated the understanding of the human body and illness for centuries. The theory was that the human body was made up of and affected by four humours: blood, phlegm, yellow bile and black bile. Wellness lay in the correct balance of these four elements and most illness was thought to be a result of an imbalance — a belief that dictated medical treatments.

Blood was related to the air element and caused a person to be lively and happy. Phlegm equated to elemental water and drew out traits such as patience and tolerance, but made a person introverted. Yellow bile was the fire humour and stoked anger and passion with the body, but also gave great reserves of energy. Black bile represented earth and caused sadness and melancholy, making those with this as their dominant humour moody and prone to depression.

Medieval medical theory taught that diet, a poor environment or disease caused the humours to move out of balance within the body, allowing the prevailing trait of the predominant humour to dictate the mood of the person. Diet was an important feature of correcting the humours, with certain foods capable of cancelling out imbalances. Medicines tended to be herbal remedies that…