The dream is a well-known experience in the routine life. It is the image and thought being occurred during the sleep, and the complex reaction of our mental world to the event of everyday. In particular, there are so many opinions of the reason why people have a dream and this thesis is telling about the physical and pathological changes in the human as one of that various opinions. The aspects of this thesis are often founded in the diverse texts of oriental Medicine, including the Internal Classics(내경), and there were some cases that regarded the dream as diagnostic object and put to clinical uses. These attempts were not only tried out by particular orient thoght, also the ancient Greeks thought that the dream would represent important informations about the health. But, these ideas have been treated lightly by the impacts of the western medicine since the modern age. Straightforwardly, before the psycho-analytics was not development, most of the doctors and scientists regarded the dream as things like dregs of mind. The central operating bodies of the dream are the Spirit(신) and Hon and Beak(혼백), and the Spirit(신) is more essential part between the two.