Hirudotherapy

Hirudotherapy is the scientific name for the use of leeches, esp. medicinal leech, for medicinal purposes. Used since medieval times to relieve inflammations and to correct supposed "imbalances of the four humours", then discredited for centuries, hirudotherapy is now used to encourage regrowth of blood vessels after surgery to delicate areas such as mucous membranes, particularly in cases where arterial regrowth was successful but venous regrowth was less so.

Hirudotherapy functions by the constant application of the multiple anticoagulants found in leech saliva, in particular hirudin, and by the leeches' constant removal of excess blood.