Ischemic colitis is the most common form of intestinal ischemia. It manifests as a spectrum of injury from transient self-limited ischemia involving the mucosa and submucosa to acute fulminant ischemia with transmural infarction that may progress to necrosis and death. Although there are a variety of causes, the most common mechanism is an acute, self-limited compromise in intestinal blood flow. Patients typically have mild abdominal pain and tenderness over the involved segment of bowel. There is usually passage of blood mixed with stool, but hemodynamically significant bleeding is unusual. Although computed tomography may have suggestive findings, colonoscopy is the procedure of choice for diagnosis. Supportive care with intravenous fluids, optimization of hemodynamic status, avoidance of vasoconstrictive drugs, bowel rest, and empiric antibiotics will produce clinical improvement within 1 to 2 days in most patients. Twenty percent of patients will have development of peritonitis or may deteriorate despite conservative management and will require surgery.