Thoracic "empyemas" appear often in the Hippocratic Corpus and with detailed descriptions of their etiology and clinical manifestation. To find the precise thoracic location suffering from "empyema," the physician asks the patient to turn on one side and inspects there for pain. The Hippocratic physicians give a very detailed description of "empyemas" caused by "peripneumonia," which is an illness resembling today's pneumonia. The proposed therapeutic method in this case, thoracostomy and drainage of the empyema, constitutes a cornerstone of our surgical heritage, appearing for the first time in the Hippocratic texts.