The Hippocratic Oath The oath is still used today. It makes clear that doctors are not magicians. They have to keep high standards of treatment and behaviour and to work for the benefit of patients rather than to make themselves rich. Books The Hippocratic Collection contains books which doctors used for centuries. This collection is important because it is the first detailed list of symptoms and treatments. Doctors continued to use the theories of Hippocrates as the basis of their work for hundreds of years. Observing Hippocrates taught how vital it was to examine patients and note down their symptoms and the development of diseases. Recording Hippocrates encourages doctors to record what they observed, to help them in their diagnosis and to pass knowledge on to others. Causes of disease Hippocrates developed the theory of the four humours to explain the causes of disease. We now know that this theory was wrong but it dominated medical treatments for many centuries. Natural treatments Hippocrates encouraged people to look for natural treatments for illnesses rather than going to the gods for help.