Risk is the probability that within a certain time some expected negative event will take place. In medicine risk can be related to a decision or to some intrinsic factors which are associated with the probability of the occurrence of a disease. Decisions can be necessary in the individual life with respect to the question of visiting a physician or performing a certain diagnostic or therapeutic procedure. The introduction of new pharmaceutical or technical products into medical use are another set (...) of decisions which can generate certain risks. Intrinsic or inherent risk factors are a set of variables or signs and symptoms which indicate the presence of a certain probability that some disease or event, e.g., arteriosclerosis or sudden infant death syndrome, may occur. Risk is always related to judgement. In a decision process cost, effectiveness and profit can be used to estimate the magnitude of the risk to be taken. In a similar way the problems in connection with an inherent risk are primarily related to the recognition of the magnitude of risk and to the possibility of prophylactic measures.In our own area of research, the sudden infant death syndrome (SIDS) is an event where only risk factors can be observed. We point at two facts in this context: Highly complex patterns of symptoms like behaviour can better be classified by intuitive Gestalt perception. A medical procedure like induction of labour can itself become a risk factor. (shrink)