When I was much younger, it was not uncommon to purchase leeches at the local drug store and use them to treat a black eye. Modern medicine in the United States would generally find such use archaic and abhorrent.

Not so in Russia. Leeches are still widely prescribed there — about 10 million every year — in many cases as a low-cost substitute for blood thinners like warfarin. In that country, a medicinal leech costs less than $1, and a typical treatment requires three to seven of these ravenous bloodsuckers.

According to the New York Times, leech treatments take 30 to 40 minutes, though the resulting wounds ooze blood for an additional six hours or so until the natural anticoagulant in leech venom wears off.

That venom is the focus in Russian medicine. It is prescribed as a preventive treatment for stroke and heart disease at a fraction of the cost for drugs used as anticoagulants. (In the last few years the Food and Drug Administration (FDA) has approved three new oral blood thinner drugs: Pradaxa, Xarleto and Eliquis. All three are primarily used to reduce the risk of atrial fibrillation.) Leeches are also used in Russia to treat glaucoma, prostatitis, high blood pressure and many more ailments. Patients are encouraged to use leeches in conjunction with standard drug treatments.

Medical leeches sell for 90 cents each in Russia, compared to $15 or more here. Fortunately, leeches can be used multiple times.

Leeches are creeping back into Western medicine, and in the U.S., 6,000 leeches are used to remove excess blood from severed body parts that have been reattached.

Leeches actually have FDA approval and are classified as medical devices. However, it should be noted that the medicinal leech has been used for eons.

Its use was first recorded in 200 B.C., and according to historians, such therapy began even sooner in India. In the Napoleonic era, the Empress Josephine was treated with leeches after a fall. Napoleon’s military surgeon advocated using 30 to 50 leeches at a time, enough to draw up to 1½ quarts of blood. (Leeches can consume over five times their body weight.) During that time it was estimated than more than 40 million leeches were used annually in France. In the late 1800s, leeching became so popular that the common preferred variety became an endangered species. The great advantage was that leeches could extract blood with very little pain and could be used on almost any part of the body. By the early part of the 20th century, however, the use of leeches in medical treatment went into steep decline.

Leeches are closely related to earthworms and lugworms; they thrive in mountain lakes, desert oases and even polar oceans. There are 650 known species, and unlike other worms, leeches have a sucker at each end, one for feeding and one for hanging on. The medicinal leech (Hirudo medicinalis) has three jaws, with 100 teeth in each.

The specific value of leech therapy is related to the properties of its bite. The slimy creatures manufacture a wide portfolio of substances that help keep the blood flowing once they have attached themselves to a host. They don't just latch on, they pump out anticoagulants that prevent the wound they create from clotting too quickly. Leeches secrete hirudin, a direct thrombin inhibitor.

Other substances produced by leeches include a vasodilator, hyaluronidase, and an anesthetic. Hyaluroni-dase is an enzyme that increases the permeability of leech saliva through human tissue and it exhibits antibiotic properties as well.

The leech is also unique in that its digestive tract contains a single bacteria species, Aeromonas veronii. This organism may inhibit the proliferation of other bacteria.

In the late 20th century there was a renewed interest in leeches by the lay and scientific communities. This stemmed from clinical results in 1960 by two Yugoslavian surgeons. They described their use of leeches to relieve venous congestion caused by skin implants. The work was published in the British Journal of Plastic Surgery. Since then leeches have been used to repair grafted skin flaps and in the removal of congested venous blood in digital, scalp and external ear re-implantations. Leeches have also been studied where other treatments have failed to provide relief for the pain and inflammation of osteoarthritis. Other uses include breast reconstruction after a mastectomy, black eyes and for reduction of postoperative swelling.

Who knows — leeches may soon available from your local pharmacy.

Max Sherman is a medical writer and pharmacist retired from the medical device industry. He has taught college courses on regulatory and compliance issues at Ivy Tech, Grace College and Butler University. Sherman has an unquenchable thirst for knowledge on all levels. Eclectic Science, the title of his column, will touch on famed doctors and scientists, human senses, aging, various diseases, and little-known facts about many species, including their contributions to scientific research. He can be reached by email at maxsherman339@gmail.com.