The present invention provides a more effective gastrointestinal function promoter. The present invention also provides a method for the prophylaxis or improvement of functional gastrointestinal disorders, a method for appetite regulation and the like. The present invention also provides a method for screening for a substance capable of promoting a gastrointestinal function. The present invention provides a gastrointestinal function promoter containing a T1R agonist as an active ingredient and a method for the prophylaxis or improvement of functional gastrointestinal disorders, a method for appetite regulation and the like by administering a T1R agonist. The present invention also provides a method of screening for a substance capable of promoting a gastrointestinal function which method uses a cell expressing T1R receptor.