[Comprehension and evaluation of drug risks through spontaneous notification].

Risk/benefit analysis of drugs requires not only the reporting and documentation of adverse drug reactions in clinical trials but also a spontaneous reporting system for the detection of rare adverse reactions to drugs. A central aspect of any spontaneous reporting system is assessment of causality on the basis of detailed case histories. However, besides the qualitative description of adverse drug reactions, information about the incidence of such reactions has to be obtained as well so that their frequency, and thus the risk involved, can be established.