Citizens’ deaths in police custody are sometimes attributed to “excited delirium syndrome” (ExDS). This terminology is rejected by the American Medical Association and the American Psychiatric Association. ExDS has no demonstrable pathology but has been proposed as predisposing to sudden death, thus exonerating police. Ketamine use during arrests complicates manner of death. ExDS deaths trigger lawsuits claiming police misconduct and excessive force. Defendant officers and municipalities have used ExDS to distance themselves from liability, using expert testimony from nonpsychiatrists. This argument is expressed despite lack of autopsy findings, the false idea that mental illness itself can lead to sudden death, and the absence of consistent diagnostic criteria. This article traces the history of ExDS and reviews the arguments for and against its use in psychiatry and law enforcement. The authors conclude that the label is medically unreliable, has eroded confidence in police-citizen interactions, and obscures dynamics of deaths in custody.