Methods for maintaining or improving the gastrointestinal health of an animal by administering a gastrointestinal health maintaining or improving amount of at least one banana musa fruit to the animal susceptible to or suffering from poor gastrointestinal health. In one embodiment, banana is administered to the animal to prevent or treat diarrhea or to improve stool quality. In other embodiments, the banana musa fruit is administered in conjunction with one or more of foods, prebiotics, probiotics, and anti-diarrhea drugs.