Advances in Medical Knowledge

Ancient and Medieval Medical Knowledge (c.500-1500)

Galen’s theory of the four humours: Influenced by Hippocrates, Galen’s ideas held sway for centuries. The belief was that health rested on balancing blood, phlegm, black bile, and yellow bile.
Reliance on religious healing: Many saw disease as a divine punishment or trial. Prayers, relics, and pilgrimages were common forms of seeking healing.
Herbal remedies: Knowledge of herbs and their medicinal properties was widespread, often leading to effective treatments for a range of illnesses.
Surgery: Although surgeons lacked understanding of infection and anaesthesia, many techniques, such as bloodletting, amputations, and cataract surgery, were in practice.

Paracelsus and chemical medicine: Paracelsus rejected humoural theory and promoted the use of chemicals in medicine. His emphasis on observing patients and studying disease influenced later medical approaches.
Discovery of circulation: William Harvey’s discovery of blood circulation in the human body dramatically changed the understanding of how the body works, challenging Galenic ideas.
Anatomy: Autopsies and human dissections became more commonplace, improving understanding of the human body and contributing to advancements in surgery.

Vaccination: Edward Jenner’s work in the late 18th century led to the development of the world’s first vaccine for smallpox, marking a seismic shift in preventative health care.
Germ theory: In the 19th century, Louis Pasteur and Robert Koch established germ theory—the understanding that certain diseases are caused by invading organisms.
Anaesthetics and antiseptics: Joseph Lister’s use of carbolic acid as an antiseptic, along with the development of anaesthetics in the 19th century, transformed the success rate and pain level of surgeries.
X-Rays and medical imaging: From the discovery of X-rays at the end of the 19th century, medical imaging has developed, including ultrasound, CT, MRI, and PET scans, revolutionising diagnostics.
Antibiotics: The discovery of penicillin and subsequent development of different antibiotics has significantly lowered death rates from bacterial infections since the 20th century.
Genetics: The late 20th and early 21st centuries have seen significant progress in understanding genetics and its role in disease, opening potential routes for treatments—like gene therapy and precision medicine.