Blood letting and the therapeutic use of Hirudo medicinalis date back to ancient Egypt and the beginning of civilisation. Their popularity has varied over the years, reaching such a peak in Europe between 1825 and 1850 that supplies were exhausted. Towards the end of the century they fell out of favour and, during this period, the leech, once used by the physicians of emperors and influential academic surgeons, became associated with lay therapists and quackery. Leeches have enjoyed a renaissance in reconstructive microsurgery during the last 15 years, having been used by maxillofacial Br. J. Oral Maxillofac. Surg 41 (2003) 44 and other reconstructive surgeons to aid salvage of compromised microvascular free tissue transfers Laryngoscope 108 (1998) 1129; Br. J. Plast. Surg. 34 (1984) 358, replanted digits Int. J. Microsurg. 3 (1981) 265, ears Ann. Plast. Surg. 43 (1999) 427, lips Plast. Reconstr. Surg. 102 (1998) 358; J. Reconstr. Microsurg. 9 (1993) 327 and nasal tips Br. J. Oral Maxillofac. Surg. 36 (1998) 462. Peer-reviewed evidence suggests that the survival of compromised, venous-congested tissues is improved by early application of a leech J. Reconstr. Microsurg. 12 (1996) 165; Arch. Otolaryngol. Head Neck Surg. 114 (1988) 1395; Br. J. Plast. Surg. 45 (1992) 235. Leeches have also recently been used to treat a wide range of conditions, including periorbital haematomas Br. J. Ophthalmol. 75 (1991) 755, severe macroglossia Otolaryngol. Head Neck Surg. 125 (2001) 649; J. Laryngol. Otol. 109 (1995) 442 and purpura fulminans Ann. Plast. Surg. 35 (1995) 300. The first medicinal leech farm, Biopharm, was set up in Swansea in 1981 by Dr Roy Sawyer, and now supplies leeches to hospitals all over the world. In this paper, we summarise the history of treatment with Hirudo medicinalis from its origin to the present day, and take a brief look at the possible future of the annelid.