Pharmacovigilance plays an important role in a number of reporting, and documentation as well as in the evaluation of marketed medical products and checking the safety of the patient during the clinical trials which follow the rules of ethical committees. This committee created a safety procedure by which human clinical trials are done. From that data, adverse drug reaction is measured. pharmacovigilance works on many other things like safety databases, customized safety, cell center function, safety signal management, customized safety surveillance, individual case reporting, literature monitoring and media monitoring search, adverse event and product complaint management, eudravigilance reporting, clinical adjudication committee management, safety narrative writing. In clinical trials, pharmacovigilance plays an important role so that there is no harm to the human subject.