&NA;The case of a 60‐year‐old man with massive lower intestinal bleeding, secondary to erosion of an abnormally large submucosal muscular artery in the ascending colon, is reported The bleeding site was localized by angiography. The clinicopathologic presentation of this case is identical to Dieulafoy's disease, which occurs almost exclusively in the stomach. Three similar patients with lesions also located in the ascending colon have been reported in the English medical literature.