This chapter covers acute psychiatric emergencies and the associated legal and care-related issues. It begins with patient assessment with both a mental and physical examination checklist. It lists the common organic causes of psychiatric illness, available local services, and risk factors for successful suicide attempts. The presentation and management of different psychiatric conditions is described, including psychosis, depression, mania, anxiety disorders, and personality disorders. The legal and ethical issues, including the 1983 and 2007 Mental Health Acts, are explained. Methods of managing the violent patient are also described.