According to an article in Al Jazeera: ".. this freshwater parasite preys on large mammals and has 10 eyes and stomachs, six hearts, and a sucker equipped with three jaws. The jaws sport 90 teeth that can penetrate human skin within seconds and leave a bite that resembles a tiny Mercedes Benz logo." While the bite is rather painful it also releases many proteins and enzymes that have beneficial effects. According to Yelena Titova, who heads a production laboratory at the world's largest leech farm at Udelnaya near Moscow, the bite releases drugs that stimulate blood circulation, metabolism, generation of blood cells, lower cholesterol, and aid people with heart conditions, glaucoma, diabetes and infertility. There may be some marketing hype in these claims but even the US FDA since 2004 has allowed the marketing of leeches as "medical devices" when it approved an application by a French company. Leeches were already widely used in the US and companies that raised and sold them have been allowed to continue doing so but a law passed in 1976 required new companies to receive approval from the FDA. The FDA reports that leeches are helpful in healing skin grafts by removing blood pooled under the skin after grafts. They also can restore lost circulation in blocked veins by removing pooled blood. Being classified as "medical devices" has probably contributed to a comeback of hirudotherapy in mainstream western medicine. The use of leeches dates back to ancient times: Leeching, or hirudotherapy, was widely used in ancient Egypt, India and China since at least 1500 BC. The bloodsucking worm became such a ubiquitous staple of medieval European medicine that the very word "leech" originates from Anglo-Saxon "laece", or doctor. European doctors believed that leeching drains "bad blood" and helps balance patients' bodily fluids. Hirudotherapy does not always work as in the notorious case of Lord Byron the poet in 1824: On Apr. 9, while out riding, he was drenched to the skin by a sudden rainstorm and took chill. Within two hours he complained of fever and rheumatic pains. Though he opposed the use of leeches, he finally relented, and they took a pound of blood from his body. He became weaker, but he was bled twice more, fainting each time. His brain was inflamed, but doctors decided that strong stimulants, Peruvian bark and wine, were his only hope. Who knows perhaps it was the Peruvian bark and wine that ultimately did him in. He fell asleep and did not wake up. The three story laboratory in Udelnaya was built during the Stalin era It raises up to three million bloodsuckers annually. They hatch from fuzzy white cocoons and are fed on cow's blood, and are allowed to grow for about a year before being sold to health clinics. However, some are killed and powdered and turned into creams, shampoos, and lotions, some quite expensive. Natalia Lepyoshkina smiles as she displays a handful of leeches and says: "See how beautiful they are?" Here is an image of some of leeches at the farm. Lepyoshkina is one of about two dozen leech growers at the farm. She has worked there for 30 years and talks of the leeches as if they are her children: "We have to nurture them, nurse them, raise them like our own children." Not all doctors are enthusiastic about the use of leeches. Doctor Yelena Malysheva who has a very popular TV show on national Channel One claims that leech therapy is "outdated" and "miserable". Certainly in the west, the practice has been in decline compared to the 19th century or ancient Greece:In ancient Greece and 19th-century Europe, leeches were the predominant medical device for bloodletting, a procedure by which practitioners sought to help balance the body's "humors" (phlegm, blood and bile) by simply allowing the subject to bleed for a bit. Bloodletting was prescribed to treat a variety of conditions, from a black eye, headache and fever to obesity and melancholia, and in 1883, French medical professionals imported more than 40 million leeches for this purpose [sources: Rubin, Mestel]. Nevertheless, as with many other traditional medical remedies, modern medicine is discovering that ancient practices and remedies do often have proven value.