Medieval medicine is famous in the popular imagination for its gore, its strangeness, and its lack of similarities to modern medical practices. You might have heard of bloodletting, commonly practiced throughout Europe in the Middle Ages and the early modern period to treat illnesses such as Plague and Smallpox, and even Epilepsy. Bloodletting was so common that it contributed to the death of George Washington during an attempt to treat a minor illness. Despite this, the practice was used until the 1920s in multiple procedures, particularly cardiac treatments. Why was this? The answer stems back to ancient authors such as Hippocrates and Galen, who articulated the basis of understandings of the body and thereby dictated diagnosis and treatment in Europe until the twentieth century. The answer is – of course – the four humours. 

Belief in the four humours was introduced by Hippocrates and his successors in the age of antiquity, as part of a process of combining naturalistic knowledge, philosophy, and ancient science to devise a complete understanding of the human body and how it interacts with the world around it. Put simply, the four humours were: blood (sanguine), yellow bile (choleric), black bile (melancholic), and phlegm (phlegmatic). These four substances were organised around the four elements, the four qualities of cold, hot, moist, and dry, as well as around the four seasons, and even around planets. These four bodily substances in harmony with each other meant an individual was healthy, but any humour out of balance constituted illness. The theory of the four humours in ancient, medieval, and early modern minds underpinned understanding of the human body’s interaction with the environment and defined for centuries the way in which disease and illness were thought to work, how emotions fluctuated, and the impacts of age and sex on health. Paster highlights this, arguing that the “early moderns” thought men’s bodies were hotter and women’s colder as a result of natural humoral differences. Furthermore, you may already be aware of the way in which this theory has trickled town into common vocabulary. Indeed, black bile was also known as melancholia, and a tip in humoral balance towards melancholia would often lead to a markedly depressed mood. In other words, one would be feeling melancholic. 

If imbalance meant disease, attempts needed to be made by individuals and persons knowledgeable in medicine to restore balance. This could be achieved by adjusting diet, exercise, and by managing the body’s excrements. It was believed that every individual person had a different and unique humoral makeup. As aforementioned, the factors controlling this included sex, age, temperament and many more. Therefore, each imbalanced case needed to be considered carefully and closely. Particular attention was paid to the climate in which the sick person resided. Was this place hot and dry? Did the patient in fact need to be somewhere cold and dry in order to rebalance their humours? The environment had an instrumental impact on humours and therefore on treatment of disease. 

So, what of the bloodletting mentioned before? As blood (or sanguine) was one of the four humours, it was understood that an excess of blood could lead to imbalanced humours and, therefore, to sickness. Naturally, blood would be let via leeches, to reduce the amount of blood in the diseased body and restore balance to the humours. The legacy of this theory can still be glimpsed today. Bloodletting was such a key cure that so-called “barber-surgeons” featured prominently into the early modern period, and indeed the red and white pole outside modern barber shops symbolises this profession: red for the blood let, white for the bandages needed after. To modern readers bloodletting seems foolish and risky. It did, after all, partly result in the death of George Washington himself. In 1799, Washington came down with an illness which his medical attendants decided to treat through the established practice of bloodletting. That night they let 40 per cent of Washington’s blood, proving detrimental to his chances of survival. However, ancient authorities did not fear bloodletting, because it was believed that blood was constantly being made in the liver and would replenish the depleted stores. There was no fear of bleeding a patient out. 

With today’s medical knowledge, aided by technological innovations and remarkable discoveries, it can be easy to trivialise the theory of the four humours, to render it a foolish mistake made by the intellectually inferior people of the past. However, it is important to stress how, while the theory may not have proven to be medically sound, it was incredibly logical. This may sound strange, but the theory of the four humours, when contextualised within the dense and complex framework of belief systems and scientific capabilities of antiquity, makes an awful lot of sense. The concept of disease resulting from imbalance within the body is a seductive one. And to ancients who did not have the knowledge that we can so easily access, this theory makes clear and logical sense. Especially in medieval England, where the theories of Galen, including that of the four humours, were accepted by the religious authorities and complied with biblical rules. Furthermore, there is a misconception that the people of the past, especially medieval people, knew little of medicine or the body. The theory of the four humours and the complex way in which it connects to the environment, to the many known planets, to the earth’s elements and so many more, disproves this misconception decisively.  

Written by Amy Hendrie  

Bibliography  

Hartnell, Jack. Medieval Bodies: Life, Death and Art in the Middle Ages. London: W.W. Norton, 2018.  

Paster, Gail Kern. “Unbearable Coldness of Female Being: Women’s Imperfection and the Humoral Economy.” English Literary Renaissance 28, no. 3 (1998): 416-440. 

“Shakespeare and the Four Humors” Exhibition developed and produced by the National Library of Medicine, National Institutes of Health. Accessed at: https://www.nlm.nih.gov/exhibition/shakespeare/fourhumors.html.