This document provides an introduction to adverse drug reactions (ADRs), including definitions, classifications, detection methods, reporting procedures, and management. It defines pharmacovigilance as monitoring for and preventing ADRs. ADRs can be classified into several types based on their mechanism and timing. Detection methods include pre-marketing clinical trials as well as post-marketing surveillance like spontaneous reporting and cohort or case-control studies. Standardized reporting forms are used to communicate suspected ADRs to monitoring centers. Causality, severity, and predictability are then assessed to manage ADR risks.