A towering figure in the history of medicine was the physician Hippocrates of Kos (ca. 460 BC – ca. 370 BC), considered the "father of modern medicine."
TheHippocratic Corpus is a collection of around seventy early medical works from ancient Greece strongly associated with Hippocrates and his students. Most famously, Hippocrates invented the Hippocratic Oath for physicians, which is still relevant and in use today.
The existence of the Hippocratic Oath implies that this "Hippocratic" medicine was practiced by a group of professional physicians bound (at least among themselves) by a strict ethical code. Aspiring students normally paid a fee for training (a provision is made for exceptions) and entered into a virtual family relationship with his teacher. This training included some oral instruction and probably hands-on experience as the teacher's assistant, since the Oath assumes that the student will be interacting with patients. The Oath also places limits on what the physician may or may not do ("To please no one will I prescribe a deadly drug") and intriguingly hints at the existence of another class of professional specialists, perhaps akin to surgeons ("I will leave this operation to be performed by practitioners, specialists in this art").
Hippocrates and his followers were first to describe many diseases and medical conditions. He is given credit for the first description of clubbing of the fingers, an important diagnostic sign in chronic suppurative lung disease, lung cancer and cyanotic heart disease. For this reason, clubbed fingers are sometimes referred to as "Hippocratic fingers". Hippocrates was also the first physician to describe Hippocratic face in Prognosis. Shakespeare famously alludes to this description when writing of Falstaff's death in Act II, Scene iii. of Henry V.
Hippocrates began to categorize illnesses as acute, chronic, endemic and epidemic, and use terms such as, "exacerbation, relapse, resolution, crisis, paroxysm, peak, and convalescence." Another of Hippocrates's major contributions may be found in his descriptions of the symptomatology, physical findings, surgical treatment and prognosis of thoracic empyema, i.e. suppuration of the lining of the chest cavity and hair loss and baldness.