This study takes as its subject the polemical text attributed to Hippocrates On Ancient Medicine , which challenges the views of the causes and treatment of illness prevalent at the time of its composition (around 400 BC). The main emphasis of the study is placed on the analysis of the author’s scientific polemic. With this approach, a text which has previously tended to be regarded as a document of the history of ideas can for the first time be acknowledged as a literary work of the first order.