Drug reactions commonly involve the nervous system, resulting in a variety of disorders that may be serious and even life-threatening and may mimic many naturally occurring neurologic disorders. Most drug-induced disorders are potentially reversible if the offending agent is identified and withdrawn. The possibility of an iatrogenic condition should be considered in any patient with neurologic symptoms, and a full drug history should always be obtained. The spectrum of drug-induced neurologic disorders is wide, ranging from disturbances of neuromuscular or autonomic function to seizures, movement disorders, syndromes of raised intracranial pressure, stroke, cognitive dysfunction, and encephalopathic states.