The intestinal wall is a selectively permeable barrier that separates the intestinal lumen from the body's internal environment. Disturbances in its permeability can lead to excessive activation of the enteric immune system and the development of endotoxemia, characterized by increased levels of bacterial lipopolysaccharides (LPS) in the blood, causing chronic low-intensity inflammation. This review covers the structure of the intestinal barrier, the influence of gut microbiota on permeability through the regulation of tight junction proteins, mucus synthesis/degradation, and antioxidant effects, the molecular mechanisms of pro-inflammatory responses activated by bacterial invasion via TLR4-induced signaling cascades, and the impact of nutrition and exercise on intestinal permeability. The review highlights the potential of non-pharmacological approaches, such as specific diets and regular physical exercise, to maintain the integrity of the intestinal barrier and prevent associated inflammatory processes. Early age increases in intestinal permeability may have a hormetic effect, contributing to immune system development. The review also discusses the role of gut microbiota in maintaining immune homeostasis, the impact of diet and exercise on intestinal permeability, and the potential benefits of probiotics in maintaining barrier function. Overall, the review provides insights into preventing excessive intestinal barrier permeability and associated inflammatory processes, emphasizing the importance of a healthy gut ecosystem and efficient intestinal barrier operation.The intestinal wall is a selectively permeable barrier that separates the intestinal lumen from the body's internal environment. Disturbances in its permeability can lead to excessive activation of the enteric immune system and the development of endotoxemia, characterized by increased levels of bacterial lipopolysaccharides (LPS) in the blood, causing chronic low-intensity inflammation. This review covers the structure of the intestinal barrier, the influence of gut microbiota on permeability through the regulation of tight junction proteins, mucus synthesis/degradation, and antioxidant effects, the molecular mechanisms of pro-inflammatory responses activated by bacterial invasion via TLR4-induced signaling cascades, and the impact of nutrition and exercise on intestinal permeability. The review highlights the potential of non-pharmacological approaches, such as specific diets and regular physical exercise, to maintain the integrity of the intestinal barrier and prevent associated inflammatory processes. Early age increases in intestinal permeability may have a hormetic effect, contributing to immune system development. The review also discusses the role of gut microbiota in maintaining immune homeostasis, the impact of diet and exercise on intestinal permeability, and the potential benefits of probiotics in maintaining barrier function. Overall, the review provides insights into preventing excessive intestinal barrier permeability and associated inflammatory processes, emphasizing the importance of a healthy gut ecosystem and efficient intestinal barrier operation.