During the course of treatment or after, some drugs prescribed to patients produce certain effects other than those desired or expected. These adverse effects cause concern both to the physician and the patient, adding to the spiralling costs of medical treatment, morbidity and mortality. They rank between the fourth and sixth leading cause of death.

The science of and activities relating to the detection, assessment, understanding and prevention of adverse effects or any other medicine-related problems is called pharmacovigilance, as defined by the World Health Organization. This article provides information on some recent label changes of drugs, withdrawals from the market and standard methods of adverse drug reaction (ADR) monitoring with examples. It also gives some practical details about the reporting system of ADRs in India and its applications.