Traditionally, doctors have been trained to treat a patient on the basis of his or her personal clinical needs. Increasingly, however, the practice of medicine has been influenced by patients social circumstances and more recently by community- and government driven national priorities. One critical aspect of these widening influences has been the cost of medical care which, as medicine becomes more complex, has been rising sharply. Thus health economics has become an integral part of the provision of health care. Cost-of-illness studies now appear commonly in medical publications. Such studies aim to identify and measure all the costs of a particular disease, including, where feasible, the direct, indirect and intangible dimensions. The information obtained is intended to help the development of health policies, nationally and internationally. The application of information from such studies is, however, proving controversial. Firstly, doctors still see their clinical responsibilities to patients as a priority. Secondly, cost-of-care studies are often criticised for excluding broader economic aspects of health care — for example, analyses of the cost-effectiveness of prevention as well as the treatment of illness. This requires assessment of potential and actual outcomes as well as the costs of illnesses. Even so, the increasing complexity of medicine, with its commensurately rising costs affecting both state- and privately funded medical care, makes it inevitable that the cost of maintaining a population’s good health will be a growing factor in the provision of health care that seems bound to impinge on how doctors are enabled to treat their individual patients.