Thirty-five consecutive patients with acute hematochezia, negative gastric aspirates, and negative sigmoidoscopy underwent urgent colonoscopy after Golytely purgation. Mucosal visualization was excellent. Colonic bleeding lesions were identified in 24 of 35 patients, and hemorrhage originating proximal to the ileoceal valve was documented in three of these 35 patients. Therapeutic endoscopic electrocautery, employed in 12 of 35 patients, was effective in 11. The peroral preparation was well tolerated, and there were no complications of the preparation or of colonoscopy. The data suggest that urgent colonoscopy following Golytely purgation is a safe, sensitive, and specific diagnostic procedure that provides an opportunity for early nonoperative treatment of acute colonic hemorrhage.