The present investigation focuses on deliberate metaphor use in medical texts of the fifth and fourth century BCE. My analysis concentrates above all on the relation between deliberate metaphors and argumentation in order to define more precisely which role metaphors played in the development of Greek medical speculations. My aim is to show that not only is early Greek medical discourse “metaphorical” in that it often consciously applies terms beyond their primary sphere of reference, but early Greek medical argumentation is influenced by metaphor use to a great extent. To show that, I shall try to answer the following questions: which purposes do deliberate metaphors fulfil, and to what extent are they powerful tools in early Greek medical speculations? In which way and to what extent do metaphors influence argumentation, and how do they elicit productive reasoning at the beginning of Greek medical discourse?