The present invention provides a therapeutic agent and a prophylactic agent for a gastrointestinal disease. A peptide having an amino acid sequence represented by Ser-Ser-Ser-Arg or a pharmaceutically acceptable salt thereof promotes wound healing in a gastrointestinal mucosal tissue, and is therefore useful as a therapeutic agent or a prophylactic agent for a gastrointestinal disease. Further, when (a) a peptide having an amino acid sequence represented by Ser-Ser-Ser-Arg or a pharmaceutically acceptable salt thereof and (b) a peptide having an amino acid sequence represented by Phe-Gly-Leu-Met-NH 2 or a pharmaceutically acceptable salt thereof are administered in combination, these medicaments act synergistically and can significantly promote wound healing in a gastrointestinal mucosal tissue.
