Bloodletting as a medical practice was probably introduced in Ancient Greece. The first written account of it was by the famed physician Hippocrates in the 5th century BC. The ancients believed in the body’s humors (blood, phlegm, black bile, yellow bile) which corresponded to the elements of earth, air, fire, and water, which for them represented the four most primal building blocks of all matter.  Long before the existence of cells, atoms, bacteria, or DNA was known, medical diagnoses were, at best, shots in the dark. For physicians in the ancient world, disease resulted from an imbalance in these four humors, This could clearly be seen when females menstruated; ridding the body of excess blood automatically restored a woman to good health. And so they concluded that forcing a patient to vomit, urinate, defecate, or bleed was a sure-fire cure all for all illnesses.
    As the Greek Empire declined and the Muslim empire expanded, the Arabs preserved Greek medical texts and translated them into Arabic. As the Muslim empire spread across North Africa and into southern Europe, they brought these texts along. Then when the Christians started to successfully fight back and reconqueror their own lands, they took possession of these books, translated them into Latin and the use of bloodletting as a medical technique exploded during the Middle Ages where it continued to be the primary source of treatment until the end of the 18th century.
    The most common method of bloodletting was known as “phlebotomy” or “venesection” which simply consisted of drawing out quantities of blood with a syringe, usually from a large vein or artery. Another method was called “scarification” which used a specialized set of tools to puncture the patient’s skin. A simple syringe could be utilized as well as a device with sawtoothed blades that rotated by turning a handle attached to gears. Heated vacuum cups were attached to the scars to draw out the blood which was then collected in cups. One other method of bloodletting was through the use of leeches attached to the sick person’s body. The bloodletting treatment concluded when the patient lost so much blood that they fainted.
    During the 18th century, the science of diagnosis took off dramatically and by the end of the century bloodletting was thought to be of no medical value whatsoever. While its use declined, some physicians continued to use it as treatment. One reason given for this was that traditional medicine was believed to be superior to modern scientific methods. The other major problem being that, while the science of diagnosis became more fine-tuned, the science of medical cures for ailments lagged far behind. Therefore, some doctors, even though they knew bloodletting had no beneficial effects, continued to use it because any treatment was thought to be better than no treatment. By the mid-nineteenth century, statistical studies on bloodletting in pneumonia patients showed it to have no effect other than some possible placebo effects. The practice died out except in some rare cases of frauds, folk medicine practitioners, snake oil salesmen, and so-called “alternative medicine”.