Tropical disease and parasite expert Dr James Logan is getting up close and personal with leeches. He wants to know more about how the humble leech is making a comeback in the world of medicine.
In the example of a severed finger, the finger needs a steady flow of blood to prevent the flesh from dying. A leech can be attached, preventing blood from clotting and helping to maintain the flow of oxygen around the finger. They can also be used for helping to relieve pains associated with ‘tennis elbow’ and other repetitive strain injuries. Down on the leech farm, Dr James decides to give it a go. The natural anaesthetics and anticoagulants in leech saliva assist in the flow of clean, oxygenated blood to his dodgy knee, aiding healing.
from : http://www.channel4embarrassingillnesses.com/episodes/episode-guides/embarrassing-bodies-series-6/episode-4–bristol/leeches/