When honey didn't do the trick, the ancient Egyptians used bloodletting to treat patients with dangerous infections. The treatment grew out of a medical theory that the body contained four fluids, or "humors," which included blood, phlegm, black bile and yellow bile. (From this, we get words like "choleric" and "phlegmatic" to describe people's personalities.) It was believed that for a person to be healthy, those four fluids had to be kept in balance, and that infections resulted not from microbes — which were unknown in those days — but from an excess of blood [source: Columbus].
Sometimes, doctors would bleed a patient by making an incision in a vein or artery. They also used a technique called cupping, in which heated glass cups were placed on the skin. That created a vacuum and broke numerous small blood vessels, so that the patient bled over a larger area beneath the skin. Sometimes leeches were used for bloodletting [source: Columbus].
Though it seems dangerous and grisly today, bloodletting may actually have had some effectiveness against certain types of bacteria, at least in the early stages of an infection. The microbes require iron to reproduce themselves, and depriving them of the red blood cells that carry iron might make it more difficult for the invaders to sustain the infection [source: Columbus].