Objectives. To create a data base (BIFAP) with information provided by primary care doctors from the National Health System who use a computer at work, to evaluate its validity as a source of pharmaco-epidemiological information and to use it for the study of the efficacy and safety of medicines. Justification. Some data bases, such as the British GPRD, have shown great efficiency in pharmaco-epidemiological research and in analysis of alarm signals in pharmacovigilance: primary care doctors are in a very good position to obtain clinical information from their patients. It is recommended that the impact of medicines on various populations is evaluated, including of course those medicines most used in Spain. Pilot phase. January 2000-end of 2003. 300-500 doctors took part: a) monitoring of certain recommendations on recording; b) dispatch every 2 or 3 months to the Spanish Medicines Agency (AEM) of anonymous information with its origin encrypted (basic demographic details, morbidity, prescriptions, other data of epidemiological relevance), which are analysed by computer to check whether they meet adequate recording standards; c) despatch to the AEM of copies of anonymous clinical reports from small samples of patients (for BIFAP validation studies). Feasibility and perspectives. If BIFAP were viable, a standardised procedure for its use and protocols to support it as a research tool would be put in place.