Bloodletting is one of the oldest medical practices, having been practiced since ancient times, including the Mesopotamians, the Greeks, the Mayans, and the Aztecs. In Greece, bloodletting was standard practice around the time of Hippocrates and Herophilos. Herophilos (335-280 BC) was a Greek physician who was the first scientist to systematically perform scientific dissections of human cadavers and is deemed to be the first anatomist. Hippocrates of Cos (460BC-370BC) was also a Greek physician and is referred to as the "father of medicine." He was the first physician to reject superstitions, legends and beliefs that credited supernatural or divine forces causing illness. In the Act of June 28, 2004, the Food and Drug administration (FDA) cleared for the first time the commercial marketing of Medicinal Leeches for medicinal purposes. Today the rest of the world is catching on as leeches are on the cusp of not only enjoying a revival for known health benefits, but there are constant new discoveries based on thorough medical research about positive effects of the substances produced by medicinal leeches, that are later induced by leeches into human body (and/or animals as well ) during the hirudotherapy treatments. This book traces the use of leeches for bloodletting therapy from ancient Greek times to the Chapin Harris era in the 1840s to modern day usage by plastic surgeons. The leech is described as both a parasite and a therapeutic agent. In this book author comprises the possible indications of leech therapy along with procedures, safety concerns, historical perspective, surgical operative standards, and contraindication of the same described in traditional system of medicine.