How are medicines monitored in order to ensure that new side effects are detected?
The main way in which the MHRA monitors medicines safety is to collect reports of possible or suspected side effects from patients and health professionals. These reports are made on ‘Yellow Cards’. Pharmaceutical companies also have a legal obligation to pass on reports that they receive about suspected side effects of their products that are defined as serious. These reports are made on ‘Yellow Card’ reporting forms. We enter Yellow Card reports onto a specialised database that allows rapid processing and analysis of the reports. Since the Yellow Card Scheme was set up in 1964, over 600,000 UK Yellow Cards have been received. Yellow Card reports are evaluated each week to find possible previously unidentified hazards and other new information on the side effects of medicines. We also evaluate information on medicines safety from other data sources from the United Kingdom and from around the world, including the MHRA General Practice Research Database (more information is available at
