An independent, non-regulatory drug surveillance research unit has been established at the University of Southampton. Its first task will be to set up a prescription-event monitoring scheme in general practice to enable the pattern of adverse events, as distinct from suspected adverse reactions associated with new drugs to be compared with that of older medicines. Prescriptions for selected drugs will identify patients and a simple questionnaire, designed to be completed in under five minutes, will be used to obtain the required information. Medical opinions about causation need not be given, and the scheme will not interfere with normal prescribing practice.