Shock is a final common pathway associated with regularly encountered emergencies including myocardial infarction, microbial sepsis, pulmonary embolism, significant trauma, and anaphylaxis. Shock results in impaired tissue perfusion, cellular hypoxia, and metabolic derangements that cause cellular injury. The clinical manifestations and prognosis of shock are largely dependent on the etiology and duration of insult. It is important that emergency physicians, familiar with the broad differential diagnosis of shock, be prepared to rapidly recognize, resuscitate, and target appropriate therapies aimed at correcting the underlying process. This article focuses on the basic pathophysiology of shock states and reviews the rationale regarding vasoactive drug therapy for cardiovascular support of shock within an emergency environment.