This master thesis explores health as a primarily active process and what role theoretical and practical medicine should play in health. Health is divided up into four rooms: the room of the theoretician who works in medicine, the meeting between the theoretician and practician, the meeting between practician and patient, and lastly the individual’s cultural room. By phenomenologically unveiling the transmutation of life defined as death within the cartesian framework of mind-body dualism and its influences on modern Western medicine it becomes apparent that health as defined by biomedicine (lack of disease) is a problematic concept in regard to the experience of being ill in the individual’s room, which is the phenomenological starting point. In the West there exists a cultural tendency among both natural scientists and laypersons to use natural science and medical theory to explain and give meaning to individual diseases and healths, which has also lead to a cultural crisis in the ill individuals’ identity as the cartesian mind-body dualism is more complex than two opposing forces – it is more correct to describe this relation of mind and body identity as a ‘trialism’. The thesis mainly rests on the works of Drew Leder and Jenny Slatman; their works on health and illness in relation to cartesian dualism, and on their concepts of authentic materialism and differential materialism respectively, to formulate a phenomenological theory of health (from the room of the individual) understood as primarily an activity. It concludes that health within the individual’s room is an activity in the now that consists in accepting one’s bodily state and the choices one has made in life to land oneself in the body one now experiences. A healthy choice is grounded in a will to be one’s self, to be one’s own body, although one does not coincide with it. The role of practical medicine is to help the individual want to be themselves, their own body, – by working with the two concepts of health presented as the theoretical health (absence of disease) and the phenomenological (will to be oneself).