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. The following diseases are also possible causes of increased permeability of gastrointestinal mucosa: 1. Gastric cancer Gastric cancer is one of the most common malignant tumors in China, and its incidence rate ranks first among digestive tract tumors in China. Gastric cancer can occur at any age, but it is more common between 40 and 60 years old, more men than women, about 3:1. The average life expectancy of untreated patients is about 13 months. 2.Graft-versus-host disease (GVHD) is a systemic disease with multi-system damage (skin, esophagus, gastrointestinal, liver, etc.) after bone marrow transplantation (BMT), which is one of the important causes of death. 3.Gastrointestinal tract with cancer syndrome Gastrointestinal tract with cancer syndrome refers to some syndromes associated with certain cancerous tumors of the digestive system. It does not include the general systemic effects of tumors, such as jaundice, fever, wasting, etc., nor does it refer to the extra-gastrointestinal manifestations of classical endocrine tumors of the digestive tract.