Agitation can present as an emergency in the course of numerous psychiatric conditions including intoxication, schizophrenia, bipolar disorder, and delirium. This article reviews relevant literature regarding the definition, etiology, measurement, and management of episodic agitation and pays particular attention to intramuscular treatments. The impact of changes in methodology between the era of first- and second-generation antipsychotics, the implications of those changes for external validity of studies of second-generation studies, and the recent evolution of expert consensus are discussed.