Intestinal barrier permeability is a critical factor in maintaining health, as it prevents the entry of harmful substances into the body while allowing nutrients to pass through. This review discusses the influence of gut microbiota, nutrition, and exercise on intestinal barrier function. The intestinal barrier is composed of multiple layers, including a mucous layer, epithelial cells, and the lamina propria, which together form a selective barrier. The gut microbiota plays a key role in regulating the permeability of the intestinal wall through the modulation of tight junction proteins, mucus synthesis, and antioxidant effects. Dysbiosis, or an imbalance in the gut microbiota, can lead to increased intestinal permeability and the translocation of harmful bacteria and their components into the bloodstream, causing inflammation and disease. Nutrition significantly affects intestinal barrier function. A diet rich in beneficial bacteria, such as those found in fermented dairy products, can enhance the integrity of the intestinal barrier. Polyphenolic compounds, such as quercetin and kaempferol, also improve intestinal barrier function by increasing the expression of tight junction proteins and reducing inflammation. Exercise, particularly high-intensity exercise, can induce heat stress and hypoxia, which may affect intestinal permeability. However, controlled exercise at an early age may be beneficial for immune system development through hormetic mechanisms. The review highlights the importance of maintaining a balanced diet and regular physical activity to support intestinal barrier function and prevent diseases associated with increased permeability. Probiotics, such as Lactobacillus and Bifidobacterium, can help maintain intestinal barrier integrity by modulating the expression of tight junction proteins and reducing inflammation. Overall, the review emphasizes the need for a holistic approach to maintaining intestinal health through diet, exercise, and the gut microbiota.Intestinal barrier permeability is a critical factor in maintaining health, as it prevents the entry of harmful substances into the body while allowing nutrients to pass through. This review discusses the influence of gut microbiota, nutrition, and exercise on intestinal barrier function. The intestinal barrier is composed of multiple layers, including a mucous layer, epithelial cells, and the lamina propria, which together form a selective barrier. The gut microbiota plays a key role in regulating the permeability of the intestinal wall through the modulation of tight junction proteins, mucus synthesis, and antioxidant effects. Dysbiosis, or an imbalance in the gut microbiota, can lead to increased intestinal permeability and the translocation of harmful bacteria and their components into the bloodstream, causing inflammation and disease. Nutrition significantly affects intestinal barrier function. A diet rich in beneficial bacteria, such as those found in fermented dairy products, can enhance the integrity of the intestinal barrier. Polyphenolic compounds, such as quercetin and kaempferol, also improve intestinal barrier function by increasing the expression of tight junction proteins and reducing inflammation. Exercise, particularly high-intensity exercise, can induce heat stress and hypoxia, which may affect intestinal permeability. However, controlled exercise at an early age may be beneficial for immune system development through hormetic mechanisms. The review highlights the importance of maintaining a balanced diet and regular physical activity to support intestinal barrier function and prevent diseases associated with increased permeability. Probiotics, such as Lactobacillus and Bifidobacterium, can help maintain intestinal barrier integrity by modulating the expression of tight junction proteins and reducing inflammation. Overall, the review emphasizes the need for a holistic approach to maintaining intestinal health through diet, exercise, and the gut microbiota.