However, the achievements of the writers of the Corpus, the practitioners of Hippocratic medicine and the actions of Hippocrates himself were often commingled; thus very little is known about what Hippocrates actually thought, wrote, and did. Hippocrates is commonly portrayed as the paragon of the ancient physician, and credited with coining the Hippocratic Oath, which is still relevant and in use today. He is also credited with greatly advancing the systematic study of clinical medicine, summing up the medical knowledge of previous schools, and prescribing practices for physicians through the Hippocratic Corpus and other works.
Soranus said that Hippocrates learned medicine from his father and grandfather (Hippocrates I), and studied other subjects with Democritus and Gorgias. Hippocrates was probably trained at the asklepieion of Kos, and took lessons from the Thracian physician Herodicus of Selymbria. Plato mentions Hippocrates in two of his dialogues: in Protagoras, Plato describes Hippocrates as "Hippocrates of Kos, the Asclepiad"; while in Phaedrus, Plato suggests that "Hippocrates the Asclepiad" thought that a complete knowledge of the nature of the body was necessary for medicine. Hippocrates taught and practiced medicine throughout his life, traveling at least as far as Thessaly, Thrace, and the Sea of Marmara. Several different accounts of his death exist. He died, probably in Larissa, at the age of 83, 85 or 90, though some say he lived to be well over 100.
Ancient Greek schools of medicine were split (into the Knidian and Koan) on how to deal with disease. The Knidian school of medicine focused on diagnosis. Medicine at the time of Hippocrates knew almost nothing of human anatomy and physiology because of the Greek taboo forbidding the dissection of humans. The Knidian school consequently failed to distinguish when one disease caused many possible series of symptoms. The Hippocratic school or Koan school achieved greater success by applying general diagnoses and passive treatments. Its focus was on patient care and prognosis, not diagnosis. It could effectively treat diseases and allowed for a great development in clinical practice.
Hippocratic medicine was humble and passive. The therapeutic approach was based on "the healing power of nature" ("vis medicatrix naturae" in Latin). According to this doctrine, the body contains within itself the power to re-balance the four humours and heal itself (physis). Hippocratic therapy focused on simply easing this natural process. To this end, Hippocrates believed "rest and immobilization [were] of capital importance." In general, the Hippocratic medicine was very kind to the patient; treatment was gentle, and emphasized keeping the patient clean and sterile. For example, only clean water or wine were ever used on wounds, though "dry" treatment was preferable. Soothing balms were sometimes employed.
The Hippocratic School gave importance to the clinical doctrines of observation and documentation. These doctrines dictate that physicians record their findings and their medicinal methods in a very clear and objective manner, so that these records may be passed down and employed by other physicians. Hippocrates made careful, regular note of many symptoms including complexion, pulse, fever, pains, movement, and excretions. He is said to have measured a patient's pulse when taking a case history to discover whether the patient was lying. Hippocrates extended clinical observations into family history and environment. "To him medicine owes the art of clinical inspection and observation." For this reason, he may more properly be termed as the "Father of Medicine".
The Hippocratic school of medicine described well the ailments of the human rectum and the treatment thereof, despite the school's poor theory of medicine. Hemorrhoids, for instance, though believed to be caused by an excess of bile and phlegm, were treated by Hippocratic physicians in relatively advanced ways. Cautery and excision are described in the Hippocratic Corpus, in addition to the preferred methods: ligating the hemorrhoids and drying them with a hot iron. Other treatments such as applying various salves are suggested as well. Today, "treatment [for hemorrhoids] still includes burning, strangling, and excising." Also, some of the fundamental concepts of proctoscopy outlined in the Corpus are still in use. For example, the uses of the rectal speculum, a common medical device, are discussed in the Hippocratic Corpus. This constitutes the earliest recorded reference to endoscopy. Hippocrates often used lifestyle modifications such as diet and exercise to treat diseases such as diabetes, what is today called lifestyle medicine. He is often quoted with "Let food be your medicine, and medicine be your food" and "Walking is man's best medicine", however the quote "Let food be your medicine" appears to be a misquotation and its exact origin remains unknown.