In Ancient times, the use of animal excrement for healing was recorded in the Eber's Papyrus. Dating back to 1500 B.C., a range of feces, from dog and gazelle to donkey, could be used to not only treat wounds but to keep bad spirits away. Some women would place crocodile dung into their vaginas, believing it could serve as a contraceptive. Bloodletting is the process of draining one's blood, which became prominent around 460 to 370 BC., blood, phlegm, black bile, and yellow bile. An imbalance was thought to make a person ill; migraines and fever were among issues treated with draining blood out of a vein or artery. Leeches were key to the bloodletting process, and through the ages, have been used as a treatment for infection, skin diseases, dental afflictions, and nervous system abnormalities, shares PBS. But perhaps their most miraculous attribute has kept them relevant in today's medicine leeches secrete specific peptides and proteins that increase wound blood flow, by preventing clotting.