To effectively treat an aging and increasingly complex patient population, emergency physicians and other acute-care providers must be comfortable with the use of vasopressors, inotropes, and chronotropes. These medicines are used to augment the cardiovascular function of critically ill patients. Each class of medication produces a different hemodynamic effect. Some agents produce only one of these actions, whereas others have multiple effects. For the emergency physician, these agents are used with the explicit goal of preserving vital organ perfusion during acute and severe illness. This article reviews the physiologic receptors targeted by such drugs, common agents used, and specific clinical indications for their use.