The use of the term `disease' in medicine is discussed, with particular reference to the issues raised by Kennedy (I) and the definition proposed by Campbell, Scadding and Roberts (2). Certain difficulties arising from this definition are considered, and a revised set of definitions is suggested, based on a distinction between diseasedness, contrasted both with health and with other sorts of problems, and nosological categories used to distinguish conditions calling for different treatments. The difference is stressed between those aspects of (...) medical decision-making which call for judgment on scientific grounds and those of the sort referred to by Kennedy, which involve ethical and political judgments. (shrink)