Postmarketing surveillance is the practice of monitoring the safety of a pharmaceutical drug or medical device after it has been released on the market and is an important part of the science of pharmacovigilance. It refers to the monitoring of drugs once they reach the market after clinical trials. It evaluates drugs taken by individuals under a wide range of circumstances over an extended period of time. Such surveillance is much more likely to detect previously unrecognized positive or negative effects that may be associated with a drug. The majority of postmarketing surveillance concern adverse drug reactions monitoring and evaluation, including the existence of particular causal effects, frequency of and risk factors for certain outcomes, economic consequences of therapy, and characterization of drug use in clinical practice. Postmarketing surveillance uses a number of approaches to monitor drug and device safety, including spontaneous reporting databases, prescription event monitoring, electronic health records, patient registries, and record linkage between health databases. These data are reviewed to highlight potential safety concerns in a process known as data mining. Pharmacovigilance Journal discusses the latest research innovations and important developments in this field. Pharmacovigilance Journal is interested in the special fields related to the topics of this Journal.