The present invention relates to a method of stimulating the motility of the gastrointestinal system in a subject in need thereof, wherein the subject suffers from maladies (i.e., disorders or diseases) of the gastrointestinal system. The method comprises administering to a subject in need thereof a therapeutically effective amount of a growth hormone secretagogue compound or a pharmaceutically acceptable salt, hydrate or solvate thereof. The growth hormone secretagogue can be co-administered with a laxative, a H2 receptor antagonist, a serotonin 5-HT4 agonist, an antacid, an opioid antagonist, a proton pump inhibitor, a motilin receptor agonist, dopamine antagonist, a cholinergic agonist, a cholinesterase inhibitor, somatostatin, octreotide, or any combination thereof.