BACKGROUND: Schizophrenia and bipolar disorders are chronic illnesses that commonly present with symptoms of acute agitation and aggression. These symptoms must be managed rapidly to prevent potential harm to the patient and others, including their caregivers, peers, and health care workers. A number of treatment options are available to clinicians to manage acute agitation and aggression, including non-pharmacologic behavioral and environmental de-escalation strategies, as well as biological treatment options such as pharmacologic agents and electroconvulsive therapy. We summarize the available biological treatment options for patients with schizophrenia or bipolar disorder presenting with acute agitation or aggression in the inpatient setting, focusing on antipsychotics.