Heart Views

: 2021  |  Volume : 22  |  Issue : 4  |  Page : 307--308

Medicine from galen to the present: A short history

Rachel Hajar 
 Department of Cardiology, Heart Hospital, Hamad Medical Corporation, Doha, Qatar

Correspondence Address:
Dr. Rachel Hajar
Department of Cardiology, Heart Hospital, Hamad Medical Corporation, P. O. Box: 3050, Doha

How to cite this article:
Hajar R. Medicine from galen to the present: A short history.Heart Views 2021;22:307-308

How to cite this URL:
Hajar R. Medicine from galen to the present: A short history. Heart Views [serial online] 2021 [cited 2023 Jun 2 ];22:307-308
Available from: https://www.heartviews.org/text.asp?2021/22/4/307/337538

Full Text


Medieval medicine was heavily influenced by the ancient Greeks and Romans, in particular by Hippocrates and Galen.

 Galen'S Four Humors

Galen believed that the body contained four important liquids called humors, which were phlegm, blood, yellow bile, and black bile. These humors must remain in balance for a person to remain healthy. If there was too much of one humor, illness occurred. The excess fluid was removed; for example, blood was removed by bleeding and excess bile could be removed with a purgative. The theory of the humors was an accepted medical teaching until the Renaissance (the Renaissance lasted from the 14th to the 17th century).

After the Renaissance, patients were told to do everything in moderation-not to eat, drink, or exercise too much. This probably helped people lead healthy lives.

 Astrology and Medieval Doctors

The ancient Sumerian and Babylonians in the 3rd millennium BC used horoscopic astrology by observing the seasonal movement of the sun, moon, and planets. The Babylonian connected the beliefs of divine intervention in their everyday life to space and time.

Medieval doctors (i.e., of the Middle Ages or the Dark Ages, which began around 476 A. D.) also used astrology for they believed that the movement of the stars affected people's health. Each part of the body was associated with an astrological sign, so that physicians carried out bleeding when the moon was in the correct position. Physicians, therefore, needed knowledge of astrology to treat patients.

 Stagnation of Medical Knowledge in the West and Role of the Church

Then, medical knowledge stagnated in Europe in the Dark Ages in large part due to the Church which forbade dissection and encouraged prayer and superstition. It emphasized the following of “authority” rather than observation and investigation. The Church insisted that people follow Galen's writings (the Church favored Galen because his writings show that he believed in the soul). The Church also encouraged the belief that disease was punishment from God and relied on prayers to the saints to superstition to cure them of disease. This led to fatalism and prevented people from investigation of cures. The Church, in general, forbade the dissection of corpses and discouraged experiments. As a result, there was economic, intellectual, and cultural decline.

 The Crusades and Meeting with Muslims

The Church encouraged people to go on Crusades to the Holy Land where they came into contact with the Muslim world. The Muslim doctors were more knowledgeable than their European counterparts and brought back improvements in medical knowledge. In 1258, Baghdad was destroyed by the Mongols, and much ancient knowledge that had been retained in the east but lost to the west was carried back to the west by translation from Arabic texts.

 The Renaissance

As a consequence, there was renewed interest in the knowledge of the ancient Greeks and Romans. This brought about the so-called European Renaissance or revival in the arts and sciences. However, these ideas encouraged people to think for themselves and soon they began to challenge the teachings of Hippocrates and Galen. Doctors such as Andreas Vesalius and William Harvey influenced by earlier cultures began to experiment and to develop new ideas about anatomy and the circulation of the blood. New weapons in warfare forced battlefield doctors to think of new ways to treat wounds.

Renaissance artists, such as Michelangelo and Leonardo Da Vinci, studied the human body closely to replicate it in art which helped further medical knowledge. The invention of mechanical printing in 1440 facilitated and disseminated the spread of this new knowledge.

Though medical knowledge had moved forward, the impact on everyday health was limited. At the beginning of the 19th century, scientists still did not understand what caused disease. There were a few individuals who made important contributions such as Joseph Lister, Louis Pasteure, and Robert Koch. There were other notable scientists and doctors who advanced our medical knowledge like in Cardiology and surgery.

 The Deoxyribonucleic Acid

Then the deoxyribonucleic acid (DNA) was discovered by James Watson and Francis Crick in the mid-19th century. It has been said that Francis Crick walked into a pub and announced, “We have found the secret of life.” The “we” in this announcement was he and his collaborator and later fellow Nobel prize winner, James Watson, and their “secret of life” was the double helix structure of DNA.

 The Human Genome Project

The Human Genome Project (HGP) started at the end of the 20th century, in 1990, and completed in 2003. A genome is an organism's complete set of DNA, a chemical compound that contains the genetic instructions needed to develop and direct the activities of every organism. A genome is an organism's DNA molecules and are made of two twisting, paired strands. Each strand is made of four chemical units, called nucleotide bases. The bases are adenine (A), thymine (T), guanine (G), and cytosine (C). The human genome contains approximately 3 billion of these base pairs, which reside in the 23 pairs of chromosomes within the nucleus of all of our cells. Mapping the HGP involved scientists from 18 countries and showed the importance of collaboration in advancing medical knowledge.

The HGP was one of the great feats of exploration in history. It gave us the ability, for the first time, to read nature's complete genetic blueprint for building a human being.

 Dawn of Genetic Medicine

The HGP opened a whole new field in medicine, genetic medicine. Genetic materials such as DNA and RNA delivered into the body as a therapy. They are a promising new class of medicine that was not possible even a short time ago. Advancements in science and technology are changing the way we define disease, develop drugs, and prescribe treatments with an explosion of insights into the role of genetics in infectious diseases, cancer, and rare diseases. Genetic medicines are an emerging technology with the potential to be developed as personalized medicines.

For example, the present endemic COVID 19 caused SARS CoV2 is a virus currently responsible for our diminished way of life. The vaccine for the coronavirus pandemic was developed from messenger RNA (mRNA), a recent innovation in genetic medicine. The mRNA vaccines at the vanguard of the COVID-19 pandemic show how genetic vaccines have not only the potential for high potency, low-cost manufacturing, and safe administration but also the capacity for rapid development.

Researchers are testing several approaches to gene therapy, including replacing a disease-causing mutated gene with a healthy gene, inactivating or “knocking out” a malfunctioning mutated gene, and introducing a new gene to help fight a disease.

Gene therapy is a promising application for genetic medicines for a number of diseases such as inherited disorders, viral infection, and cancers. This technique allows doctors to treat a disorder by delivering a gene into a patient instead of using drugs or surgery. The idea of germline gene therapy is controversial. While it could spare future generations in a family from having a particular genetic disorder, it might affect the development of a fetus or have long-term side effects that are not yet known.

The HGP has also created other ethical, legal, and social dilemmas which is beyond the scope of this article to discuss.

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Conflicts of interest

There are no conflicts of interest.