Adverse drug reactions (ADRs) are harmful or unintended effects that occur after taking a medication. These reactions can range from mild side effects, like nausea or headaches, to severe complications, such as allergic reactions or organ damage. ADRs can happen to anyone, regardless of age or health status, and may be influenced by factors like dosage, drug interactions, and individual sensitivities. Monitoring and reporting ADRs is crucial for patient safety. Healthcare professionals, including doctors and pharmacists, play a key role in identifying and managing these reactions. Organizations like the Food and Drug Administration (FDA) track ADRs to improve medication safety and inform the public about potential risks.