Disclosed are methods and compositions for maintaining the integrity of the gastrointestinal tract luminal lining in a mammal, including (1) limiting epithelial cell proliferation, (2) inhibiting ulcerative lesion formation, (3) inhibiting inflammation normally associated with ulcerative diseases, and (4) stimulating the repair of ulcerative lesions and the regeneration of the luminal tissue. The methods and compositions include a therapeutically effective amount of a morphogen as defined herein.