Sometimes in reconstructive surgery, blood pools in the veins and can't flow back to the heart and lungs, which can cause tissue death. That's when leeches would be applied straight to the wound site.

It's a great time of year to meet with the giant Amazonian leech. Its kind is just emerging from the bottom muck, where they dug themselves in to wait out the three-month dry season. They'll be ...

In this short film Dr Michael Mosley interviews a surgeon who is pioneering the use of leeches in medical research. He allows a leech to attach to his arm and suck his blood, the mouth of the ...