Medicinal use of leeches in the texts of ancient Greek, Roman and early Byzantine writers.

Blood-letting was a common therapeutic method in antiquity; many means were used to draw blood, including the application of leeches. In this paper, ancient Greek, Roman and Byzantine authors up to the 7th century AD were studied, a research that provided us with references that may be divided into two groups: those related to the medicinal use of leeches, and those related to cases in which leeches were swallowed and had to be removed. In the first group, detailed descriptions of the method of usage and of the diseases requiring leeching were found. In the second group, brief reference is made to the problems caused by swallowing leeches, and to the methods used to expel them from the human organism. The earliest references to the medicinal use of leeches may be found in the writings of Theocritus (3rd century BC), Nicander (2nd century BC) and Horace (1st century BC, while the phenomenon of swallowing a leech is first mentioned in one of the Epidaurian 'iamata' dating to the 4th century BC.