Leeches have been used in the medical field for over 2500 years. They were very popular in the Middle Ages, when it was believed that many diseases were caused by an excess of blood. Up until the 19th century, leeches were used to treat everything from tonsillitis to hemorrhoids.
But did you know leeches are still used in the medical field?
Leeches are now used for patients who have suffered an amputated finger. After the amputated finger is surgically re-attached, there can be significant swelling, which can cause the surgery to fail. In that situation, leeches are applied to the re-attached finger to suck the blood out and to decrease the swelling.
The saliva of leeches secretes about 60 different proteins. Some of these work as blood thinners, and some appear to act as a natural anesthetic (which may be why leech bites are generally not painful). Leeches secrete a natural blood thinner, called “hirudin”, which is so powerful that it is being studied for other uses such as for heart attacks and strokes.
The FDA has approved Leech therapy for surgical use to help blood circulation and decrease venous congestion.
Medical leech:
Healthfacts.blog 