Taken from the name of the creature itself – Hirudo medicinalis, or the European medicinal leech – Hirudotherapy is the name used for the medical use of leeches. This practice was very common in early medicine, but is still used today.
In older times, if a sickness caused the patient to flush, the doctors assumed that the patient had too much blood in the body. The leeches were used to drain out the excess blood, thus (theoretically) restoring balance to the humors of the human body. Aelus Galenus, a Roman philosopher and physician, believed in Hippocrates’ humors theory, which stated that the humors were blood, phlegm, black bile, and yellow bile. Imbalances in the humors caused different personality “disorders” – those with too much yellow bile were melancholy, those with too much blood were sanguine, with overly social behavior.
Following the establishment of Galen’s theories, Nicander, a Greek physician, started using leeches for medicinal treatment in 200 B.C. Prior to the use of leeches, physicians would use a procedure called “cupping” to achieve bloodletting. This procedure would start with an incision to the patient’s skin, and then a cup would be placed over the incision to cause a vacuum effect to suck out the blood. Nicander discovered that leeches were far more effective and less difficult to administer than cups, and the practice took off.
In the 12th century, someone named Abd-el-latif al-Baghdadi started using leeches to clean up after surgery. He would apply the leech to suck away the excess blood. That’s more in line with the way hirudotherapy is used today. It is used in microsurgery as a way to keep the blood from coagulating. They are also used in reconstructive surgery as a means to restore blood flow to reattached body parts. Too bad they’re so creepy-looking, because they really are a sort of medical marvel.