BackgroundGreater attention to and management of anxiety and pain in pediatric patients signifies a healthy evolution in the care of children in emergency departments (EDs). Interventions to address such distress may involve unanticipated adverse effects. Midazolam, a benzodiazepine commonly administered to children for anxiolysis, may precipitate paradoxical agitation and delirium, a rare but alarming effect that warrants prompt identification and treatment. Case ReportThe case presented is that of a 4-year-old girl who received oral midazolam and developed a paradoxical reaction, which was reversed successfully with flumazenil. This is the first such case report in an ED involving a child. Why Should an Emergency Physician Be Aware of This?Emergency physicians must stay abreast of the adverse and unintended effects of the treatments provided. The literature on benzodiazepine-induced paradoxical reactions is reviewed, and flumazenil as well as other treatment options and anxiolytic alternatives are presented.