The intestine harbors a community of bacteria that is intestinal microbiota, which is a complex and highly diverse community. This review discusses the gut microbiota in piglets, including the role of intestinal homeostasis in maintaining piglet health and the various factors that influence gut microbiota. Nutritional interventions, particularly the supplementation of plant-derived polysaccharides, including dietary fiber, for weaned piglets have been shown to enhance the abundance and colonization of beneficial intestinal microbes, reduce the incidence of gastrointestinal infections, and decrease the frequency of diarrhea, thereby improving gut health and growth performance. In this context, various polysaccharides, such as those derived from