Leeches are segmented worms or annelids. They are related to the earthworm. Leeches feed on blood from other animals. Most leeches live in a fresh water environment. A smaller number of them live on land or in marine environments.

Leeching is the practice of using leeches to remove blood from patients. This form of medicine originated in ancient Egypt, India and Greece. These worms are still used today for some medical treatments.

Image: The use of leeches for bloodletting has been practiced for over 3,500 years (photo: Pat Joyce).

Ancient Leeches and Medicine

Leeches were used for medical treatment as far back as 1500 BC. A painting in an Egyptian tomb of that time shows the practice of leeching. Leeches were used in Ancient Greece, Egypt, Rome, Syria and India. Bloodletting became a popular medical treatment in the 1600’s and 1700’s in Europe.

At the time, one theory on health was that the body was composed of four humors. These were blood, phlegm, black bile and yellow bile. If the humors were not in balance, then a disease condition existed. Health practitioners used bloodletting for everything from fevers to mental illness. The practitioners used lancets, suction cups, and leeches to drain blood from a patient to balance the humors.

The way that a leech works is fairly simple. The worm attaches itself to the skin with sharp teeth. The animal then releases an anticoagulant into to the wound so blood cannot clot. Then, the annelid drinks the blood.

Modern Uses for Leeches

Leech saliva contains several useful medicinal substances. It contains an anti-coagulant, anesthetics, and a vaso-dilator. In certain medical treatments these substances have beneficial use. Today, leeches are used primarily for draining blood from damaged appendages or skin flaps.

Improving Your Reading and Thinking Skills

Think for a few moments. Try to recall the major ideas in this article. When you are done, click the box below for a list of main ideas.


How did you do? With practice, you should be able to identify many of the major ideas. You may even discover some important ideas that aren’t listed.


Bloodletting Techniques, Medical Antiques.
Hirudotherapy (Leech Therapy), BterFoundation.
Leeches are making a comeback as medical helpers, Baltimore Sun.


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4 comments on "Leeches: Blood Sucking for Health"

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Ronand Abella

Leeches is a creature that suck blood. Some doctor use leeches to suck other people’s blood.They use it so the patient hill heal. Bloodletting become popular medical treatment in the 1600’s and 1700’s in Europe. The leech is related to the earthworm. You can call the leech annelids.


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Ronand Abella

I learned the leeches is like a vampire that sook bood

Ronand Abella

I learn that the leeches is coking blood but the doctor use it