Preclinical
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Modern Bloodletting


The practice of medicine is changing at a fast pace. Research is finding new therapies for diseases once thought incurable. We are developing more effective interventions with less harmful side effects to further alleviate the burden on those with chronic illness. Recent breakthroughs have spawned clinical applications that we could not have dreamed of even half a century ago.

That being said, one of the therapies from old has withstood the test of time. Of course, I am referring to the ancient practice of bloodletting.

Methods for letting blood out from a patient’s body to cure them of disease were described in ancient Ayurvedic texts from India as early as the 7th century B.C. and the practice was employed by civilizations such as the Mesopotamians, Egyptians and ancient Greeks. This treatment was based on the system of medicine known as ‘humorism,’ which posited that an excess or deficiency in any of the primary bodily fluids directly influenced a person’s health. The four humors, were yellow bile (fire), black bile (earth), phlegm (water) and blood (air). Each humor was thought to be directly related to a set of physical qualities, a patient’s temperament, an organ and even a season of the year. Thus, based on how the patient presented, a physician could make a diagnosis of specifically which humors were out of balance.

Early physicians tried to influence the health of their patients by alleviating an overabundance of any of these humors with various techniques, including exercising patients until they sweat profusely, altering dietary intake, inducing vomiting or diarrhea, administering early diuretics to cause the patient to urinate, or by bleeding a patient of ‘excess’ blood.

During the Roman Empire, the practice of blood-letting was also based on the misunderstanding that blood was created and used up; they had yet to discover that it continuously circled through the body. Around this time, it was even thought that female menstruation was a natural model for why the treatment should be applied at other times of illness; Hippocrates believed menstruation “purged women of bad humors.”

In the dark ages, members of the clergy were often the ones performing these early forms of healing. Eventually, a snobbish distinction was made between clergy-physicians and surgeons, who at this time were known as ‘barber surgeons.’ These early barbers not only cut hair but also performed primitive surgeries, such as tooth extractions and bloodletting. The classic red and white striped barber pole we still see today represents the bloody bandages left to hang outside their offices with the brass basin at the bottom to hold the leeches often used to augment blood removal.

The fact that ancient civilizations turned to this treatment is interesting but not all that shocking. They were pretty confused about a number of things. What is shocking is that “breathing a vein,” as it was sometimes referred to, was still widespread until the mid-1800s. Benjamin Rush, a signer of the Declaration of Independence and one of America’s most distinguished early physicians, was a vocal supporter of the practice. One reason the practice held on for so long was not only because it fit into the flawed systems of how medicine was understood, but also because it seemed to have a truly positive effect in many clinical situations. If a patient had a fever, letting enough blood out would make them pale and cool.

For physicians who had used this therapy for much of their practicing lives, blood-letting continued to be a last-resort, even when it began to be clear that it had little or no therapeutic benefit. Even our first president, when afflicted by “inflammatory quinsy” of the throat in December of 1799, was bled of five pints over the course of one day. It took George’s doctors four separate bleeds before they thought they had let out enough, mentioning that Washington improved slightly after the final bloodletting. He died a short while later.

Ironically, the English term ‘bloodletting’ was replaced by the Latin term ‘phlebotomy’ as the practice was modernized (phleb- meaning vein’ and –tomia meaning ‘cutting’). It refers to removing blood from the body, both for laboratory analysis and for direct therapeutic benefit.

There are two diseases still treated by letting whole blood out of the body. One is called hereditary hemochromatosis, which is an inherited disease causing excessive absorption of dietary iron. This leads to deposition of iron in the tissues, resulting in significant organ damage. If diagnosed early enough, the harmful effects of iron overload can be prevented with routine phlebotomy, as the majority of your body’s iron is carried by the hemoglobin contained within red blood cells. The other disease still regularly treated with therapeutic phlebotomy is known as polycythemia vera. This is a myeloproliferative disease, meaning there is a genetic mutation in the bone marrow that leads to an increase in the number of mature blood cells produced.

Physicians have come a long way from trying to balance “humors.” While their understanding of disease has progressed, their logic for bloodletting is the same: to treat an overabundance.

Nathan Juergens Nathan Juergens (4 Posts)

Contributing Writer

University of Minnesota Medical School


My name is Nate and I am in the Class of 2017 at the University of Minnesota Medical School in Minneapolis. Writing is an excellent release from the hustle and rigor of medical education. It is also an activity where I get to make the decisions, which is somewhat unfamiliar at my stage of training.