The return of the leech.

Medicinal leeches (Hirudo medicinalis) have been used in medicine for thousands of years to treat a wide range of ailments. Nowadays, leeches are used successfully for only a few conditions, notably in the field of reconstructive or microsurgery, to salvage tissue flaps and skin grafts whose viability is threatened by venous congestion. The anticoagulant properties of hirudin, contained in leech saliva, may lead to wider therapeutic applications in the prevention and treatment of thromboembolic disease. Optimal care is needed when applying leeches, because their use can be complicated by serious bacterial infections.