Summary: Acute agitation and aggression are common symptoms in patients with bipolar disorder and schizophrenia. In this review, we discuss the prevalence, clinical assessment strategies, treatment options, and current Western and Chinese guidelines for the management of acute agitation and aggression in patients with bipolar disorder or schizophrenia. Among available approaches, we discuss in detail recent evidence supporting the use of intramuscular (IM) antipsychotics and some recently approved oral atypical antipsychotics for the management of acute aggression and agitation in hospitalized patients with bipolar disorder or schizophrenia presenting with acute agitation or aggression, highlighting some differences between individual antipsychotic agents.