The hypothesis that SRUS and localized CCP are analogous syndromes is supported by the similarities in clinical presentation and biopsy pathology of patients with these conditions. The theory that rectal mucosal prolapse causes SRUS and localized CCP is strengthened by the observation of like pathology in other clinical situations and various animal models in which mucosal prolapse occurs. However, rectal prolapse is not clinically demonstrable in all patients. Therefore, the definitive diagnosis of SRUS and localized CCP must depend upon the recognition of specific histopathologic features in rectal biopsy specimens from ulcer margins or otherwise abnormal mucosa. Conservative medical management is satisfactory for most patients, and surgical intervention should be reserved for highly selected patients.