Solitary ulcers of the rectum may be traumatic in origin and caused by thermometers, occasionally by digital removal of a fecal impaction, or by deviate sexual behavior. Solitary rectal ulcers may also be a manifestation of Crohn’s disease. Very rarely, ectopic gastric mucosa is their cause. For the vast majority of solitary rectal ulcers, the explanation remains unknown. Occasionally, the ulcers are accompanied by localized inflammation of the mucosa within the distal segment of the rectum with edema, erythema, and circumscribed whitish flecks in a thickened bowel wall covered by excessive secretions. The changes are found predominantly in the ventral portion of the rectum, and in contrast to the adjacent normal mucosa are strikingly apparent. Neiger refers to these changes as a proctitis terminalis simplex. Local injury, such as locally administered medication or local irritation of the mucosa, has been proposed as an etiologic factor. Conjecturally, mechanical alterations through strangulation of prolapsed areas of mucosa with compromise of the arterial blood supply in cases of chronic constipation and straining at the stool during defecation may also play a role.