Hippocrates humoral theory

The major authority for medicine in the Middle Ages was Galen of Pergamon, who worked in Rome in the second century AD. Galen adopted the humoral theory of Hippocrates, including the classification of mental illnesses, and his therapeutic recommendations were also based on the tradition of the Hippocratic school diet, vomiting, blood-letting and the administration of soporifics. 

Paracelsus went on to dismiss the theory on which the orthodox medicine of the day was based. This theory, which had originally been proposed by Hippocrates, held that the body contained four humors blood, phlegm, yellow bile, and black bile. Disease was supposedly a consequence of imbalances in these humors, and it was the physician s job to correct the imbalances. Furthermore, each humor was associated with one of the four elements. For example, a fever was clearly the result of the presence of too much fire. The humor that corresponded to fire was blood, so feverish patients should be bled. All of this was nonsense, Paracelsus said. The body was a kind of chemical laboratory, and a doctor must investigate the properties of chemical compounds to find those that would cure any specific disease. 

One of the first people to apply science to medicine was the ancient Greek physician Hippocrates (ca. 460-377 b.c.e.). Influenced by the idea that the world is composed of four substances—earth, air, fire, and water—as taught by the Greek philosopher Empedocles (ca. 495-435 b.c.e.), Hippocrates proposed that four fluids are critical in determining a person s state of health. These fluids, known as humors (from a Latin term for moisture), were called blood, yellow bile, black bile, and phlegm. According to Hippocrates, an imbalance in these humors caused disease. Later, people associated a specific temperament or personality with these humors, a theory that was one of the earliest attempts to explain moods and emotions. Blood, for example, was associated with an optimistic disposition, while black bile corresponded to depression. 

An historical aside may clarify the issues. In the medical tradition that went from the ancients (Hippocrates and Galen) through the Middle Ages until the Enlightenment, physicians basically thought about disease in terms of mechanism. The conventional theory of humors was a crude attempt to describe illness in terms of imbalances in body composition, before the invention of modern chemistry and biochemistry. 

One of the oldest theories of the causes of mental illness, propounded by Hippocrates and other physicians from Greek and Roman societies, postulated that imbalances of substances in the body, called humors, were responsible for emotional maladies, many of which resembled the major mental disorders described in American Psychiatric Association s diagnostic manual. More specifically, Hippocrates posited that disease and mental illness were caused by surpluses or deficiencies in the four humors phlegm, yellow bile, black bile, and sanguine. For example, people with too much black bile were thought to be melancholic (very sad) those with too much yellow bile were thought to be irritable. For nearly 2,000 years (from ancient times until the nineteenth century), bloodletting to restore humoral balance was a common treatment for mental illness and other ailments. 

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