Hirudo medicinalis

Hirudo medicinalis, or the European medicinal leech, is one of several species of leeches used as medicinal leeches. Other species of Hirudo sometimes also used as medicinal leeches include H. orientalis, H. troctina, and H. verbana. The Asian medicinal leech includes Hirudinaria manillensis, and the North American medicinal leech is Macrobdella decora. Medicinal leech populations were reduced significantly in many countries during the 19th century due to the high demand in medical contexts, and remain endangered in many countries today.