The increased permeability of the gastrointestinal mucosa is mostly seen in gastric and colon cancers due to necrosis and shedding of cancerous tissues, resulting in increased permeability of the corresponding gastrointestinal mucosa and loss of plasma proteins through leakage from the gastrointestinal tract. Normal gastric mucosal epithelial cells are differentiated from primitive new cells (stem cells), which are controlled by the body when to grow and when to die, and will not grow wildly out of control. Stem cells have various proto-oncogenes and oncogenes. In most cases, the characteristics of proto-oncogenes are not expressed and no carcinogenic substances are formed, so they cannot develop into cancer cells. Screening items for increased permeability of gastrointestinal mucosa: 1.Fiber gastroscopy Fiber gastroscopy is a gastroscope made of light-guided glass fiber bundle, which is inserted from the mouth through the esophagus into the stomach. It has the advantages of being soft and bendable, cold light source, clear peering, direct and safe operation. It is of great importance in the field of diagnosing diseases of the upper gastrointestinal tract. A gastroscope made of light-guided glass fiber bundle is inserted from the mouth through the esophagus into the stomach. It has the advantages of soft and bendable, cold light source, clear peeping, direct, and safe operation. 2, macronutrient examination macronutrient is the content in the organism accounted for body weight 0 . 01 % or more of the elements. These elements account for a large proportion in the body, the organism needs more. It is a necessary element for the composition of the organism. Standard healthy adults are composed of 65% oxygen, 18% carbon, 10% hydrogen, 3% nitrogen, 1.5% calcium, 1% phosphorus, 0.35% potassium, 0.25% sulfur, 0.15% sodium 0.15% chloride, 0.05% magnesium, etc. These macronutrients account for about 99.9% of body weight. The macronutrients are the elements that contain more than 0.01 % of body weight in the organism, these elements account for a larger proportion in the body, the organism needs more, and are essential elements to constitute the organism, and their examination is beneficial to our timely supplementation of macronutrients.