Galen’s Influence

Imhotep (Egypt c. 3500 B.C.), Hippocrates (KOS, Greece 460-377 B.C.), Galen (Pergamum, Asia Minor 130-201? A.D.): Those are the celebrated physicians of ancient times.

It is Galen that is the subject of this article.  Galen learned much by dissecting animals – pigs, goats, and even apes.  He worked as a physician for a gladiator school.  His repair of injured fighters also helped him to learn about the human body.  Roman law, however, prevented him from doing any dissection of human bodies, even of dead gladiators.  Hence, his understanding of the human body was limited.

He once treated a man, Eudemus, a well-known physician.  Through his effort, the man recovered.  Galen figured out that injuries in one part of the body, such as the head and neck, could affect other areas of the body such as the limbs, hands, or feet.  Galen treated the nerve in Eudemus’ neck and not his fingers that had mild paralysis.

Galen’s fame grew.  Marcus Aurelius, the emperor, hired Galen as his personal physician.  He even said, “Rome has but one physician – Galen.”

Galen’s writings and opinions became the final authority in medicine for some.  “Galen’s authority remained supreme until about the time when the colonies began to occupy the Atlantic coast of North America.  As late as the middle of the sixteenth century a London physician, who had assailed the teachings of Galen, was obliged to take back what he has said, and to hand in a written apology on penalty of expulsion from the college of physicians” (New Standard Encyclopedia).  “Medical schools used Galen’s books as textbooks for more than a thousand years.  He became the undisputed authority.  No one dared to ever differ with him” (John Hudson Tiner, Exploring the History of Medicine from the Ancient Physicians of Pharaoh to Genetic Engineering, p.14).  The Middle Ages were not good times for studying medicine, or studying anything.  The economy suffered to the point that few could afford to devote much time to medical research. Many libraries were burned when Rome fell. Writings from Hippocrates and Galen survived.  Thus, they became ” the last word in medicine” (ibid, p.13). In the 1500’s, some medical schools did little more than study Galen’s writings.

However, Galen did not have accurate knowledge of everything.  Example: Galen taught that the human breastbone had seven segments (based upon his dissection of an ape).  Andreas Vesalius ( 1514 -1564, Belgian) studied the human skeleton and found that the human skeleton has three segments. Example: He assumed that the rete mirabile, a plexus of blood vessels at the base of some animal brains was also present in humans. Example: He assumed that the lower jaw in humans was made up of two bones, as it is in dogs. Eventually Vesalius would find over 200 mistakes in Galen’s books (ibid, p.20).

William Harvey (1578-1657, English) also found that Galen’s understanding of the circulatory system incorrect.  Galen did not consider the heart a pump.He thought that the blood surging through the heart caused the beating.  Galen taught that veins carried blood away from the heart.  Galen taught that blood was constantly being manufactured by the liver and burned my the muscles. He had no concept of blood circulating.  It was in 1616 that William Harvey (an English Physician) announced before the College of Physicians lectureship, “Thus is proved a perpetual motion of the blood in a circle caused by the beating of the heart.”  Doctors who rejected his findings just quoted Galen instead of repeating his experiments (ibid, p.35).

Galen’s influence persisted. In 1796, Edward Jenner (1749-1823, English) came up with a vaccine for Small Pox.  The British Royal family, Napoleon, and Thomas Jefferson were all soon vaccinated thereafter.  He was nominated to the College of Physicians.  The doctors agreed to admit him only after he first passed a test over the teachings of Hippocrates and Galen.  He refused.

 Joseph Lister (1827-1912; an English surgeon who worked in Scotland) found Galen to be wrong on infections.  Galen taught “infections is useful. The pus cleanses wounds and helps healing” (ibid, p.87). Lister was troubled that more than half of those with compound fractures died.  He began to test antiseptics in treating such wounds.  It worked.  The death rate dropped [Note: Listerine mouthwash is named in honor of him].

Galen’s terminology is still used today.  We say that one is in “good-humor” if he feels well, and is in “ill-humor” if he feels poorly.  The term “humor” refers to fluids.  Galen theorized that there were four fluids that must be in balance to feel good.  Blood letting was based in part on this theory.


1.  “(Galen’s) books contained a curious mixture of fact, opinion and outright errors.  With his usual cheerful self-confidence, Galen stated it all as fact.  He did not keep apart what he knew as fact from what he merely believed to be true” (ibid, p.10).

We who teach should make a distinction.  When we state an opinion, we should let folks know it is such  (cf. Philemon 15).

2.  We should never place too much confidence in men.  We must do our own research (1 Thessalonians 5:21; Acts 17:11).  God and His Word is our final authority, not man.  Let us use commentaries for the evidence which they can provide, but not as popes with final authority.

3.  Many in the Middle Ages spent too much time studying Galen and not enough studying the human body.  We today can spend too much time studying what someone says about the Bible, and not enough studying the Bible itself.  Read Acts 20:32; 1 Peter 2:2.

About Bryan Hodge

I am a minister and missionary to numerous countries around the world.
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