Leeches are flattened annelids or segmented worms that live in still, warm waters of the pond or in land. They feed of blood or body fluids. 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. However, it is also important to keep it in mind as a differential diagnosis in some circumstances. This review pretends to give an actualize view of a subject that is a part of medical history.