The intestinal mucosal immune system is a specialized immune system that interacts closely with commensal microorganisms. The intestinal mucosal tissues are characterized by the way they generate immune responses to pathogens. The symbiotic flora in turn regulates the host's mucosal immunity, maintaining a dynamic balance. The disruption of the equilibrium between the two can result in intestinal disorders. This paper summarises in depth the relationships between the two and serves as a resource for future research.