Examining the naturalist and normativist concepts of health and disease this article starts with analysing the view of C. Boorse. It rejects Boorse's account of health as species-typical functioning, giving a critique of his view based on evolutionary theory of contemporary biology. Then it gives a short overview of the normativist theories of health, which can be objectivist and subjectivist theories. Rejecting the objectivist theories as philosophically untenable, it turns to the subjectivist theories of Gert and Culver, and to the view of Nordenfelt. These theories give quite a good subjectivist account of health and disease, but they do not pay enough attention to the notion of the environment, without which it is impossible to define health and disease. Starting with their definitions but introducing the notion of "reasonable social norms", the article arrives at the following definition of health: The healthier a physical or mental characteristic, process, reaction is, the more it makes it possible for the individual to adapt to reasonable social norms without pain and suffering, and the longer, and happier a life it will be able to ensure him in that society.