Acute intestinal ischemia is a gastrointestinal emergency resulting from a sudden decrement in intestinal blood flow. It may occur as a consequence of mesenteric vascular occlusion and/or hypoperfusion and may involve the small intestine or colon. Bowel infarction, sepsis, and death may result, making prompt diagnosis and management imperative. Acute mesenteric ischemia generally stems from interruption of blood flow within the superior mesenteric artery or vein, and leads to small intestinal hypoperfusion and infarction. It carries with it a mortality rate of approximately 70%, but improved survival may be achieved as a result of early diagnostic consideration, undelayed angiography, and surgical intervention, when appropriate. Acute colonic ischemia occurs typically as a result of a transient mismatch between intestinal blood flow and the metabolic demands of the colon. Although infarction may occur, colonic ischemia is often a reversible condition with mortality rates considerably lower than those witnessed in acute mesenteric ischemia. This article reviews the pathophysiology, clinical features, diagnostic, and therapeutic options applicable to patients with acute intestinal ischemia.