The dominant medical system is also sometimes labelled ‘western’ medicine, to distinguish it from ‘traditional’ medicine, which the World Health Organization and others define in relation to the cultural norms of the country in which it is practiced. The dominant medical system uses a variety of ‘scientific’ approaches to understand and combat disease. In many ways this approach has been enormously effective. Many major health problems have been subjected to intense, systematic scrutiny and there are plenty of examples of diseases that have been ‘conquered’, and where levels of understanding have reached great heights. The causes of different types of infectious disease were identified: for example, the organism responsible for tuberculosis was identified in 1882 by the German bacteriologist Robert Koch. A treatment based on sound physiological principles may or may not result in real benefit to people with the disease.