The article reviews the components and mechanisms of the mucosal barriers in the gastrointestinal tract, which are primarily composed of secreted mucus and cell surface glycocalyx. These barriers prevent infection by microorganisms that naturally inhabit the gut. The review discusses how enteric pathogens have evolved strategies to overcome these barriers, including their interactions with mucins and the mechanisms they use to disrupt and avoid the mucosal barriers. It also describes the dynamic alterations in the mucin barrier driven by host innate and adaptive immune responses to infection. The extracellular mucus barrier consists of two layers: a thinner, sterile inner layer and a thicker, non-sterile outer layer. The inner layer is physically difficult to dislodge, while the outer layer is more easily dispersed. The extracellular mucus barrier is composed of secreted mucins, nonspecific antimicrobials, and specific antimicrobial immunoglobulins. The cell surface mucin barrier, on the other hand, is a transmembrane glycoprotein rich in O-linked oligosaccharides and involved in intracellular signaling. These cell surface mucins play a crucial role in protecting against enteric pathogens that penetrate the inner mucus layer. The article also highlights the importance of mucin dynamics, which are modulated by the luminal microenvironment and immune factors. In response to infection, the production of mucins and antimicrobial molecules increases, and pathogen-specific immunoglobulins are secreted. The recognition of pathogen-associated molecular patterns (PAMPs) by Toll-like receptors (TLRs) and NOD-like receptors (NLRs) leads to the activation of inflammatory signaling pathways, which in turn induce changes in mucin expression and glycosylation. Overall, the review provides a comprehensive overview of the mucosal barriers and their interactions with enteric pathogens, emphasizing the dynamic nature of these barriers and the role of host immune responses in maintaining their integrity.The article reviews the components and mechanisms of the mucosal barriers in the gastrointestinal tract, which are primarily composed of secreted mucus and cell surface glycocalyx. These barriers prevent infection by microorganisms that naturally inhabit the gut. The review discusses how enteric pathogens have evolved strategies to overcome these barriers, including their interactions with mucins and the mechanisms they use to disrupt and avoid the mucosal barriers. It also describes the dynamic alterations in the mucin barrier driven by host innate and adaptive immune responses to infection. The extracellular mucus barrier consists of two layers: a thinner, sterile inner layer and a thicker, non-sterile outer layer. The inner layer is physically difficult to dislodge, while the outer layer is more easily dispersed. The extracellular mucus barrier is composed of secreted mucins, nonspecific antimicrobials, and specific antimicrobial immunoglobulins. The cell surface mucin barrier, on the other hand, is a transmembrane glycoprotein rich in O-linked oligosaccharides and involved in intracellular signaling. These cell surface mucins play a crucial role in protecting against enteric pathogens that penetrate the inner mucus layer. The article also highlights the importance of mucin dynamics, which are modulated by the luminal microenvironment and immune factors. In response to infection, the production of mucins and antimicrobial molecules increases, and pathogen-specific immunoglobulins are secreted. The recognition of pathogen-associated molecular patterns (PAMPs) by Toll-like receptors (TLRs) and NOD-like receptors (NLRs) leads to the activation of inflammatory signaling pathways, which in turn induce changes in mucin expression and glycosylation. Overall, the review provides a comprehensive overview of the mucosal barriers and their interactions with enteric pathogens, emphasizing the dynamic nature of these barriers and the role of host immune responses in maintaining their integrity.