Kenneth Glad
For centuries, one medical practice remained a standard treatment despite growing questions about its effectiveness. Its long history offers a striking example of how medical thinking can persist even as scientific understanding evolves.
Before thermometers, lab tests and modern scans, doctors often had to judge illness by what they could see. A flushed face, fever or swelling could look like excess blood. For centuries, removing it seemed like treatment.
Bloodletting basically survived because it gave doctors an action to take when they had little else to offer.
Before modern tests, many illnesses looked similar from the bedside. Fever, pain, weakness and swelling could point to very different conditions, but doctors often had no reliable way to tell them apart.
According to history site Historienet, the practice was used for conditions ranging from asthma and plague to mental illness and constipation.
The treatment also fit neatly with the old belief that health depended on balance inside the body. If blood appeared to be the problem, draining it seemed like a practical response.
That made bloodletting persuasive even when patients failed to recover. A death could be blamed on the illness arriving too late, not on the treatment itself.
For doctors trained in the same tradition, doing nothing could seem more dangerous than opening a vein.
Famous patients
In December 1799, former President George Washington developed a severe throat infection after riding in cold, wet weather.
Historienet writes that his doctors bled him of at least 3.75 liters of blood. As his condition worsened, Washington reportedly told them to stop, but the damage had already been done. He died later that evening.
The case became one of the best-known examples of bloodletting’s dangers because Washington was not treated by amateurs. He was attended by physicians who were acting within accepted medical thinking of their time.
King Charles II also received repeated bloodletting after falling ill in 1685. Oxford’s Centre for Evidence-Based Medicine says his doctors likely hastened his death.
The king was surrounded by physicians, but their number did not make the treatment safer. Instead, his illness became a scene of urgent intervention, with each attempt framed as another chance to save him.
His treatment showed how status could increase the risk of intervention. A royal patient drew more doctors, more urgency and more pressure to keep doing something.
For powerful patients, medical attention could become relentless. The more serious the case appeared, the more determined doctors were to act, even when their actions weakened the patient further.
Old theory
The idea rested on the belief that illness came from imbalance in the body’s fluids.
In that system, blood was only one part of a wider explanation. Health depended on the right relationship between blood, phlegm, yellow bile and black bile, and disease meant the balance had shifted.
Even after William Harvey showed in 1628 that the heart circulates blood, many physicians continued to trust older teachings.
That resistance was not unusual. Medical training, professional habit and the pressure to act all helped keep bloodletting in use long after doubts had appeared.
There was also a practical problem: Proving that a familiar treatment did not work was difficult in an age without controlled trials. If a patient recovered, the bleeding could be praised. If the patient died, the disease could be blamed.
By the 1800s, bloodletting was carried out with tools such as scarificators, small boxes fitted with spring-loaded blades.
These devices made the procedure quicker and more standardized, but not necessarily safer. They reflected a period when medicine was becoming more technical while still holding on to old assumptions about the body.
Leeches fade
Leeches became part of the same medical culture. The Institute of Biomedical Science says France imported about 40 million leeches in the 1830s.
They were placed on affected areas to draw blood more slowly than a cut vein. To doctors who linked fever and inflammation with excess blood, the method appeared controlled and useful.
Leeches also offered a kind of precision that ordinary bloodletting did not. A doctor could apply them to the skin near a wound, swelling or painful area and believe the problem was being treated at its source.
Their popularity showed how flexible the old idea had become. Whether blood was removed by blade, cup or leech, the purpose was still the same: To relieve the body of what doctors thought it could not safely keep.
The practice declined as pathology, diagnosis and germ theory changed medicine. Doctors gradually gained better explanations for infection, inflammation and disease.
As those explanations improved, bloodletting lost its place as a routine answer to almost every complaint. It became harder to defend draining a weakened patient when disease could be understood in more specific ways.
Today, controlled blood removal is used for specific conditions such as hemochromatosis and polycythemia vera, not as a cure-all.
For many earlier patients, the danger was not only disease. It was the treatment itself.
Sources: Historienet, Oxford Centre for Evidence-Based Medicine, Institute of Biomedical Science
