Quinta Essentia (Thurneisse) illustration; Alchemic approach to four humors in relation to the four elements and zodiacal signs

Caleb Reynolds answers questions no one asks.

Isn’t the humoral theory of disease just horse-hockey that should be ridiculed?

Not necessarily, would be the quick answer.

In reality, the humoral theory was the predominant medical theory and practice used in medieval Europe. The theory divides human health into four humors, which corresponded to the four elements. Blood was hot and wet like air (the theory originated in Ancient Greece). Phlegm was cold and wet like water. Yellow bile was hot and dry like fire, and black bile was cold and dry like earth. One was healthy when these four humors were balanced in all things, including diet and temperament. Pain and disease are caused by an imbalance of the humors; there was an increase in disease in the hot summers and cold winters because of the imbalance of nature: hot summers bring heat stroke, hay fever and malaria; cold winters bring frost bite, flu and pneumonia.

To our minds, living in the 21st Century, it sounds like a joke; crack-pot ideas masquerading as medicine. If you were to walk into my office and I were to tell you, “You are too sanguine. All of that beef is heating your blood, boiling your yellow bile, and throwing off your humors. You need to cool your blood with fish, which are cool and wet and will bank the fire inside of you. Also, avoid red wine, it is adding too much heat to your blood, I can see the fire of your blood in your face.” You would call me a quack and walk out.

But if I were to tell you, “You have to cut down on the red meat, it’s driving your blood pressure and your cholesterol up through the roof. Cut down on fatty meat and eat more fish, and not fried fish. And all that wine you’ve been drinking? It’s making it worse: you can have one, small glass of wine at dinner. We need to get your blood pressure under control before you have a stroke or a heart attack.” You might not like the advice, but you would accept it as proper medical advice.

People make fun of the humoral theory because it doesn’t use modern medical language, but, people of the classical and medieval world didn’t have the medical language that we have today, and they certainly didn’t have the tools and techniques that we have today. Most people today have little knowledge of what the numbers in one’s blood pressure actually mean, but we all learn something about fluid dynamics in high school, so we understand the concept that there is a certain amount of fluid pressure exerted on the vascular system whenever the heart beats. If you would bring a sphygmomanometer and stethoscope back in time and show it to Galen of Alexandria, you would have to bring a couple of physics and medical textbooks along just to explain to him how the things actually work and how they can be used to treat a patient.

For centuries, doctors used the humoral theory to treat their patients in the best way possible. Since this theory was formulated by Hippocrates and Empedocles in the 5th Century BCE, and refined in the 2nd Century AD by Galen for a more practical medical audience, most medieval doctors were using the same written works describing the theory. This meant that most doctors were making very similar decisions on how to treat patients based on balancing the humors. While we must admit that some of the decisions, and the treatments, were wrong and probably caused more harm than good, the doctors, the ones that were actually trying to help their patients, were using this theory to the best of their ability and they used language that their patients would understand.

Looking at some of the treatments for diseases that we can recognize as gout, hypertension, diabetes, or acid reflux, sound like very reasonable treatments that don’t require modern medication. The use of small doses of arsenic to treat stomach ulcers, gangrene, and leprosy, or the use of belladonna to treat asthma and hand tremors, or wormwood to remove intestinal parasites, tell us that medieval doctors understood the cause and effect nature of medication, even if they used a more simple vocabulary and didn’t adhere to modern scientific methods.

We can also state with certainty that many medieval doctors confused causation and correlation in a lot of their writing and practice. We must also acknowledge that many of the “cures” were nonsense that were passed down from doctor to apprentice over generations. There is a certain recipe for the removal of warts that can be found in medical manuscripts for a solid 500 years that involves mashing up worms and making a thick soup out of it. Now, it is possible that the original cure called for a particular species of worm that contained purpuric or salicylic acid in its digestive system, both of which are used today to remove warts topically. However, if the recipe started out as an external poultice, it appears to have migrated into a soup that could be tailor made for an individual; adding white wine if the patient was too phlegmy, or beef broth if there was too much black bile.

Then we have to contend with the fact that before proper identification and certification, anyone could call themselves a doctor and treat any person by whatever means. Literary and musical sources are filled with families paying loads of money to doctors only to receive little to no actual medical help; just empty words and empty pockets. Having a patient make and drink worm soup to remove a wart on their foot just sounds like the doctor isn’t even trying to give good value for the shilling.

So, on the one hand, quacks and pretend doctors certainly used the humoral theory to bilk their patients out of their money (the humoral theory was still being used in various forms well into the 19th Century in Europe and the Americas); but on the other hand, it was used by doctors who might not have understood the underlying principles of how the human body and diseases work, and were going solely off of what they learned by rote; and on a third hand it was used as a common medical language by doctors to describe problems and create solutions for their patients.