Philosophy of science and medicine series — I: Hippocratic Concepts of Medicine

portrait of Hippocrates
Hippocrates via Wikipedia

Philip R. Liebson, MD
Rush University, Chicago, Illinois, United States

The Hippocratic writings are the earliest of the Greek medical works. They were propounded for the most part by Hippocrates but some treatises have been credited to his disciples. Although he applies several concepts of the Aesculapian and Pythagorean schools in his treatment of medicine, he wholeheartedly refutes some of their ideas.  Medicine to him is the art or technique of curing the ill person. It is not the theoretical science of the Pythagoreans or the divine and mystical practice of the Aesculapians.

Hippocrates tries to eliminate religion from medicine. He also refutes the use of hypothesis to explain the causes of disease. He is not overly concerned with the particular causes of disease, but studies what he considers the general conditions by which disease is brought about.

To explain the workings of disease, he develops the humoral theory which supposes the human body contains four humors or juices: the melancholic, the sanguineous, the phlegmatic, and the choleric. This is based on the observation that four substances may be obtained from the blood, a yellow serum which represents the choleric humor; fibrin, which represents the phlegm; a dark clot, which is equivalent to the melancholic humor; and a red fluid, whole blood itself, which represents the sanguineous humor. They are also called the blood, phlegm, yellow bile, and black bile, originating in the heart, brain, liver, and stomach respectively. The blood is related to the hot, the phlegm to the cold, the yellow bile to the dry, and the black bile to the wet. Eucrasia—the proper balance of these juices—is indispensable for health and dyscrasis—lack of balance—brings about disease.

Hippocrates bases much of his medicine on dietetics. He believed that the origin of medicine must have occurred when men in the first stages of society discovered that food which agreed with healthy people did not necessarily agree with the sick. Certain foods produced ill health in most people while others had the opposite effect. They must also have found, according to Hippocrates, the same regimen does not apply to a disordered as to a healthy condition of the body. Physicians therefore had to study what changes of the diet are proper in particular diseases, and it was this accumulation of information that influenced the early practice of medicine.

Hippocrates, like Plato and Aristotle, equates “harmony” with what provides the best of conditions. In a healthy person, there is harmony of the bitter and the salty, sweet and acid, and sour and insipid, all maintaining themselves within the body. In food, however, excesses of these qualities are likely to occur and prove harmful. Here we see a relationship or equilibrium between organism and environment that Hippocrates stresses.

While discussing the mixture of these qualities in food, however, Hippocrates refutes certain hypotheses concerning the cause of disease. He disagrees with the idea that diseases may be caused by excesses of hot, cold, wet, or dry. This conclusion can be borne out by experience and observation since the hot, cold, wet, and dry have never been found unmixed with any other quality. Here we find Hippocrates’ disinterest in theoretical causes of disease. He admits that if one of these four latter qualities were to be found alone in foods, disharmony of the body would occur. However since disease is never caused by one of these four latter qualities alone, it would be useless and impractical to utilize them.

On the other hand, one of these four qualities combined with certain other unique qualities could prove injurious to the body. Examples of such excesses would be excess heat and acid, or heat and salt. Fever is not caused by heat alone but from excesses of combinations indicated above. If one humor becomes dominant and the body is in a state of dyscrasia, the characteristic qualities of the humor would make themselves obvious. Hippocrates uses as an example of this an overflow of yellow bile caused by an excess of bitterness, anxiety, and burning heat that leads to a loss of strength.

The structure of the body can affect health. This is related to the power to absorb juices. For example, the parts of the body that are hollow and expanded receive humidity. The parts that are solid and round do not, and the humidity glides past.

The thickening into the forms of humors takes place through various methods. Hippocrates stresses the importance of crisis and calculations of time in such matters. In order to relieve the condition of overbalance, food that has an overbalance of the reciprocal quality should be eaten. The change brought about would be crasis, or harmony between the humors. As an example of crasis, Hippocrates shows what happens when the hot is mixed with the cold. When this occurs, they give no trouble, for the cold is rendered more moderate by the hot and the hot by the cold.

Hippocrates had tremendous confidence in the ability of the body to heal itself naturally. According to proper balance and harmony, the body would provide excess warmth when cooled and coolness when warmed. Sick persons, however, do not get rid of heat quickly. Above all, in regard to harmony and balance, all the things in man become mild and better in proportion as they are mixed with more things.

When attending a person whose body is in a state of dyscrasia, it is the duty of the physician, to learn certain things about the person. Here again we see the Hippocratic idea of the importance of the environment to the body as regards health. This is related to the general idea of the microcosm in the macrocosm. Before a doctor can adequately administer aid, he must know the relation of the particular patient to all the food or drink he takes into his system. He must know the relation of the man to his occupations. He must know what kind of disturbance disagreeable food would create and with what principle of the patient’s body it disagrees. Other general manifestations that should be taken into account that determine health and sickness deal with the general environment of the patient. These include the seasons of the year, the winds, the city or town that the patient inhabits, the liquids that the patient uses, and his mode of living. It is from knowledge of these things that the physician may proceed in treating the patient. Knowing the city inhabited by the patient would include knowing the diseases common to the city. The seasons of the year are important as a means of finding out what epidemics are common at a certain time.

Certain cities are exposed to specific endemic diseases. A city exposed to hot winds, Hippocrates relates, will have a great amount of salt water, and will be hot in the summer and cold in the winter; the heads of its inhabitants will be humid in constitution, and their bowels subject to frequent disorders, owing to the phlegm running down from the head. The forms of their bodies would be flabby and certain diseases relating to excessive flowing of humors would be endemic, such as diarrhea, and excessive menstruation in women. For a city exposed to cold winds, the waters of that city would be hard and cold. The men would be slender, and their eliminations difficult. The discharges in the upper parts of their bodies would be more fluid than in the lower parts, but bilious. Their constitutions would be such as to cause an excess of eating instead of drinking. The dryness and coldness of the waters would dispose the people to ruptures, more so than in other locales. Hippocrates here makes large use of experience and observation. Experience, he cautions, is not to be relied on too freely, though, since it is fallacious in many respects.

The physician must try to make the attendants and the patient cooperate, and he must be sure that the season is right for the drugs required. This cooperation is helped by prognosis. Hippocrates points out by explaining to the patient the omissions in his or her diet or environment which brought about the disease, the patient will be more readily persuaded of the physician’s knowledge of the circumstances surrounding the illness.

The treatment of illness would be accomplished by bathing, exercise, purging, and surgery. However, it was up to the body to regain its eucrasia. The best way to supplement the body’s restoration to its harmonic state would be accomplished by certain foods. If the body reacted well to the food, eucrasia would be gained and disease eliminated. This gradual resolution into the healthy state, or lysis, had to occur during a certain time. If the person did not get better after the time was reached, it was to be assumed that he was in a critical condition. This stress on number of days required is partly derived from the numerology of the Pythagoreans.

Certain quantitative restrictions are placed on diets of sick patients by Hippocrates. When a disease is at its height, it is necessary to use the most slender diet. A study of the diet and the patient’s elimination tells how serious the disease is at a certain stage.

During convalescence from disease, many disorders can develop. Hippocrates believes it is for the physician to know what will be injurious to the patient during recovery, such as exercise. One should know the effects of a walk or a bath unseasonably applied.

The Hippocratic corpus of specific observations of diseases is encyclopedic and too expansive to relate here. However, if we are to sum up his contributions to the scientific aspects of medicine, we should stress his treatment of the entire organism as a unit, his elimination of religion from the practice of medicine, dispensing with the idea of epilepsy as a “sacred disease”, and his attempt to eliminate philosophy from medicine.; philosophy was not necessary to medicine as medicine was to philosophy. Hippocrates discarded a priori arguments in medicine, and drew his inferences from actual observation. According to the Hippocratic corpus, philosophy freed medicine from the delusions of superstition by substituting the errors of hypothesis in their place discarding both superstitions and hypotheses and using the results of observation in place of both. Diseases were not completely natural in his opinion, and it was natural for the body to the best and the harmonious in removing disease. The less the physician tried to interfere with this natural process, the better.

Perhaps the one sentence summing up the Hippocratic concept of medicine as a material practice instead of a theoretical science can be found in On Ancient Medicine: “Whoever treats of this art should treat of things familiar to the common people”.


The Hippocratic Corpus ( or Hippocratic Collection), is a collection of around sixty early Ancient Greek medical works strongly associated with the physician Hippocrates and his teachings. Even though considered as a singular corpus that represents Hippocratic medicine, they vary (sometimes significantly) in content, age, style, and are largely of unknown authorship.

Possibly genuine works of Hippocrates used as sources for this essay:

  1. Prognostics
  2. Aphorisms
  3. On Regimen in Acute Diseases
  4. On Airs, Waters, and Places
  5. On Internal Affections
  6. On Diseases
  7. On the Humors
  8. On the Use of Liquids
  9. On Ancient Medicine

PHILIP R. LIEBSON, MD, graduated from Columbia University and the State University of New York Downstate Medical Center. He received his cardiology training at Bellevue Hospital, New York and the New York Hospital Cornell Medical Center, where he also served as faculty for several years. A professor of medicine and preventive medicine, he has been on the faculty of Rush Medical College and Rush University Medical Center since 1972 and holds the McMullan-Eybel Chair of Excellence in Clinical Cardiology.