In the annals of medical history, few creatures have played as pivotal a role as the humble leech. This bloodsucking worm, often regarded with fear and revulsion, has been a constant companion to humanity’s quest for health and healing.
The story of the leech begins in the pages of the Bible itself. In the Proverbs of Solomon, written over 2,000 years ago, the leech is mentioned as a creature of insatiable appetite, with two daughters crying out, “Give! Give!” This early reference speaks to the leech’s reputation as a relentless bloodsucker, attaching itself to its victims with a tenacity that would become legendary.
As civilizations rose and fell, the leech’s fame only grew. The ancient Greeks and Romans, with their belief in the balance of bodily fluids, saw the leech as a valuable tool in restoring equilibrium. The Greek physician Nicander, writing in the 2nd century BC, described how “blood-sucking worms” could be used to draw out stagnant blood and juices from the body. The Roman physician Galen, in the 2nd century AD, went even further, designating 45 points on the human body where leeches could be applied for maximum effect.
But it was in the Middle Ages that the leech truly came into its own. In a time when medicine was still largely a matter of superstition and guesswork, bloodletting was seen as a cure-all for everything from headaches to plague. Barber-surgeons, armed with leeches and lancets, plied their trade in public baths and private homes, letting blood flow freely in the hopes of purging the body of its ills.
The pinnacle of the leech’s popularity came in the 18th and 19th centuries, when the French physician François Broussais championed its use as a panacea for all manner of ailments. Broussais believed that most diseases were caused by “irritation” and “congestion” of the digestive system, and that the only cure was to let blood. And let blood he did, sometimes applying up to 50 leeches to a single patient in a day.
Leech Finders, from the print collection Costume of Yorkshire (1814), by artist George Walker and engravers Robert and Daniel Havell. New York Public Library
The demand for leeches was insatiable. In France alone, some 80 million leeches were used annually at the height of the craze. Women would adorn themselves with leech-shaped jewelry, and brides would even use leeches to simulate virginity on their wedding nights. The leech trade became a lucrative business, with fortunes made and lost on the backs of these slimy creatures.
But as with all fads, the leech craze eventually came to an end. In the mid-19th century, the French physician Pierre Louis used statistical analysis to demonstrate the ineffectiveness of bloodletting, and the Polish clinician Józef Dietl followed suit. The rise of pharmaceutical drugs in the late 19th century further diminished the leech’s importance.
A man having his foot treated with leeches by a country surgeon, the eponymous subject of Thomas Major’s engraving Le Chirurgien de Campagne (1747).Science History Institute
Yet the story of the leech was far from over. In 1884, the Welsh physiologist John Haycraft discovered that leech saliva contained a powerful anticoagulant, which he named hirudin. This discovery would lead to a renaissance in leech therapy in the 20th century, as researchers explored the potential of leeches to treat everything from arthritis to cancer.
Today, the leech remains a valuable tool in the medical arsenal, used in microsurgery to promote blood flow and prevent clotting. And while most of us may still recoil at the thought of these bloodsucking worms, we cannot deny the vital role they have played in the history of medicine. From the pages of the Bible to the operating rooms of the 21st century, the leech has been a constant presence, reminding us of the strange and wondrous ways in which nature can heal.
A Timeline of Leech Therapy History
3500 BC: Ancient civilisations including Egypt, Mesopotamia, Greece, the Maya, and the Aztecs utilised medicinal leech therapy (MLT) for various ailments.
1600-1300 BC: Documented literature on leech therapy appears in Vedic writings. A mural painting depicting the application of leeches was discovered in a tomb from the 18th dynasty in Thebes, Egypt.
460-370 BC: Hippocrates of Cos, a Greek physician, employed leeches to balance body humours.
335-280 BC: Herophilos, another Greek physician, also used leeches for balancing body humours.
138-185 BC: Nicander of Colophon, Greece, mentioned leeches in his poem “Alexipharmacia”.
129-199 BC: Roman physician Galen described medicinal uses for leeches.
123-50 BC: Themison of Laodicea was the first to mention leeches in Rome.
100-600 BC: Leech therapy was described in the Ayurvedic text Sushruta Samhita.
100 BC: Syrian physicians described medicinal uses for leeches.
80-40 BC: In Greece, Themison, a pupil of Asclepiades, described medicinal uses for leeches.
23-79 AD: Pliny the Elder in Rome used MLT to treat phlebitis and haemorrhoids.
129-200 AD: Aelius Galenus, a Roman physician, used leeches to balance body humours.
1510-90 AD: Ambroise Paré recommended MLT where cupping glasses could not be used, such as on haemorrhoid veins, the mouth of the womb, gums, lips, nose, and fingers.
Mid-1600s: Conrad Gessner of Zurich provided a detailed description of MLT.
1700: Jerome Negrisoli used MLT in the field of gynaecology.
1772-1838: François-Joseph-Victor Broussais, a surgeon in Napoleon’s army, advocated MLT.
1800: Dealers in Europe began the unethical practice of feeding unhealthy horses’ blood to leeches for financial gain, harming MLT’s reputation.
1809: Vitet authored “Treaty of Medical Leeches”.
1817: Thomas Bell treated an oro-antral fistula with facial swelling using MLT.
1829-1836: Parisian hospitals consumed 5-6 million leeches.
1830-1840: Europe consumed 60 million leeches per year, while Russia consumed 30 million per year.
1832: St Bartholomew’s Hospital in London used 97,300 leeches for MLT.
1835: The American government offered a $500 subsidy for successful breeding of European leeches.
1838: Richard Arnold, a Savannah physician, complained about the high cost of MLT.
1839: Chapin A. Harris used MLT for draining gums in tooth abscesses.
Mid-1800s: France imported about 40 million leeches annually, while England imported 6 million.
1840: Benjamin Rush (USA) advocated leech therapy at the Royal College of Physicians.
1850: The leech breeding business in Europe collapsed due to surplus production.
1884: John Berry Haycraft, a Birmingham chemist, discovered an anticoagulant in leech saliva.
1904: Jacoby isolated hirudin from leech saliva and named it.
1938: Leeches were removed from the French pharmacopoeia.
1980: Leeches were used to relieve venous congestion in transplant surgery.
1987: Hirudo medicinalis was included in the International Union for Conservation of Nature Invertebrate Red Data Book and Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora.
1972: MLT was removed from the French Social Security system.
1983: Henderson et al. reported the use of MLT in the post-operative treatment of a scalp avulsion case.
1985: A Harvard physician, Joseph, used MLT to reattach the ear of a five-year-old boy.
28 June 2004: The Food and Drug Administration (FDA) approved medicinal leeches as a medical device.
