This paper examines the way in which causal relations are understood in the dominant model in contemporary medicine. It argues that the causal relation is not definable in terms of the condition relation, but that in general for conditions of an occurrence to be among its causes they must answer instrumental interests in a certain way, and there are further criteria for distinguishing 'the' cause of a disease (i.e., its etiological agent) from other causal factors, which are based upon instrumental (...) interests peculiar to medicine. It also argues that diseases are complex processes of which both clinical and underlying patho-physiological manifestations are proper parts (as contrasted with effects). (shrink)