Acute massive hematochezia provides one of the greatest diagnostic and therapeutic challenges to the physician. Although most patients stop bleeding spontaneously and further evaluation can be carried on with less urgency, 10% to 15% require urgent diagnostic and therapeutic procedures. Clearly, the least invasive effective solution to the bleeding problem is generally the best, although in some cases, emergency undirected surgery may be necessary. Subtotal colectomy can be done with acceptable morbidity and mortality in this situation, provided that the surgeon is confident of a colonic source of the bleeding. An understanding of the strategies outlined above encourages the management of such patients with an eye to maximizing therapeutic benefit while minimizing morbidity.