This document provides an overview of drug hypersensitivity during anesthesia. It begins with a brief history of anesthesia practice dating back to ancient civilizations. It then defines anesthesia and introduces the topic of drug hypersensitivity during anesthesia. It discusses the epidemiology, risk factors, pathophysiology, clinical manifestations, diagnosis and treatment of drug hypersensitivity reactions that can occur during anesthesia. It also provides specific information on reactions to common anesthetic agents like neuromuscular blockers, opioids and benzodiazepines. The document includes a case report example and discusses special considerations for conditions like mastocytosis and the alpha-gal syndrome.