The entire theme of Hippocratic medicine is based on creating a balance, or homeostasis (balance), of these four humors, or re-establishing a balance that has been broken.
The basic idea of the four humors is explained by Hippocrates in his book "On Disease: Book IV." He said that the humors are formed by the food or drink taken in. There are five places in the body where humors are made: stomach, head, heart, spleen and galbladd. Each of these organs "attracts is congenerous humour to itself." (1, page 269, 270, 271)
Phlegm comes from pituitous food and drinks, and is attracted to the head. When phlegm is in abundance it causes headache. (1, page 269)
In his book "On the Different Parts of Man," he explains that when too much phlegm is produced or attracted to the brain, so much so that the brain cannot contain it, the fluid flows down one of seven pathways to cause disease. It could flow to the nose and cause catarrh and coryza. It could flow to the lungs and cause pulmonary disease. It could flow to the spine and cause spinal tuberculosis, or Pott's disease. (1, page 228-235)
Other pathways are the eyes and ears, where the various diseases of these organs are formed, including deafness an blindness. It could also flow to the muscles where it causes dropsy, the joins where it causes gout, sciatica and edema. (1, page 227)
He explains that yellow bile is produced by bilious food and drinks, and is attracted to the gallbladder. When "retarded" it results in pain. (1, page 269)
Black bile is also produced by bilious food and drinks, and is attracted to the spleen. When in excess diseases such as melancholia and hypochondria may result. (1, page 269)
Blood is attracted to the heart, and its excess results in many diseases, such as dropsy, hydropsy, and fever. (1, page 269)
A common way to resolve problems of excessive blood is to perform an operation with a blade called venesection or bleeding. However, Hippocrates rarely recommended the procedure.
Regardless of the what humor is in excess, a common way to re-establish homeostasis is by evacuating fluids from the body, such as in purging. This allowed for any impurities to exit the system in order to cleanse the body. There are essentially four pathways for this to occur: mouth, nose, rectum and urethra. (1, page 269, 271)
The way to produce purging, therefore, is to cause vomiting, expectoration, bowel movement, and urination. Another method of evacuation was to cause diaphoresis, or sweating.
The best way to cause purging in cases where a disease is caused by excessive phlegm was to cause vomiting. (1, page 282)
Causes of too much or too little of any of the humors was sometimes the result of the organ attracting too much to it, although most often it is the result of the food or drink consumed. Diseases may also arise from the air, atmosphere and season. They also arise from excessive temperatures: too hot or too cold. (1, page 226)(1, page 270, 271)
Hippocrates believed he best way to maintain homeostasis of the humors was to pay close attention to diet. He also recommended exercise and bathing. He also recommended these in ill health, and only when these simple methods didn't work did he recommend other remedies, such as purging and bleeding.
- Coxe, John Redman, translator, "Hippocrates, the Writings of Hippocrates and Galen," 1846, http://oll.libertyfund.org/titles/1988, accessed 7/6/14, also see the book online at Google books, Philadelphia, Lindsay and Blakisto
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