Anorexia is a common complication of tumor patients. Cancer pain, psychological disorder and drugs can cause appetite reduction. In addition, appetite is also influenced by nutrient level in blood, human nutrition storage, liver and gastrointestinal function status. Various factors affect the hypothalamus through different mechanisms. The hypothalamus, which is the central key to control hunger, coordinates stimuli from different sources and as a result, the patient’s appetite is reduced. Gastrointestinal tract diseases Patients with gastrointestinal tumors often suffer from intestinal lumen blockage, intestinal wall infiltration or extraluminal compression, which can cause peristaltic disorders in the gastrointestinal tract and affect the digestion and absorption of food; reduced feeding of patients with esophageal cancer can also cause impaired secretion of digestive juices; cancer of the head of the pancreas compresses the opening of the common bile duct and impairs the secretion of pancreatic juice and bile, which affects the digestion and absorption of food; the tumor itself (such as colorectal cancer) secretes mucus as well as The tumor itself (such as colorectal cancer) secretes mucus and causes secondary inflammation, so that the peristaltic function of the gastrointestinal tract is disrupted; in addition, the original gastritis and ulcerative colitis can cause abnormal digestion and absorption, and the nutritional status will also deteriorate. The nutritional status of patients with gastrointestinal tumor is affected by surgery, radiotherapy and chemotherapy, for example, gastrectomy often causes deficiency of iron, vitamin Bl2 and folic acid and reduced food intake; intestinal resection causes reduction of intestinal digestion and absorption area, pancreatic resection causes inadequate endocrine and exocrine secretion of pancreas, chemotherapy causes severe gastrointestinal reactions, manifested as nausea and vomiting, enteritis, etc., radiotherapy causes intestinal fistula and radiation enteritis, etc. The gastrointestinal tract reactions caused by chemotherapy, such as nausea and vomiting, enteritis, etc., radiotherapy-induced intestinal fistula, radiation enteritis, etc. Gastrointestinal tumor patients often have various abnormalities in energy metabolism, which are manifested as follows: changes in carbohydrate metabolism include increased glucose xenobiotic, accelerated glucose clearance and recirculation, and insulin resistance; changes in fat metabolism include increased fat mobilization, slowed serum fat profile, accelerated fat oxidation, decreased fat synthesis, and unstable increase in serum fat level; changes in protein metabolism include increased muscle protein catabolism, decreased protein synthesis, and increased protein level. The changes in protein metabolism are increased muscle protein catabolism and decreased synthesis, accelerated systemic protein conversion, and accelerated protein synthesis in the liver. All these metabolic abnormalities can cause severe malnutrition. It is now believed that cytokines also play an important role in the energy metabolism of tumor patients. For example, cytokines IL-1, I L-6, TNF-α and TNF-γ, which are derived from immunologically active cells in the body, have important effects on metabolism. TNF-α and IL-l can cause abnormal sugar, protein and fat metabolism, and IL-6 and INF-γ can cause protein and Fat metabolism abnormalities. Finally, the role of special factors secreted by tumor cells in the blood circulation, such as fat mobilization factor (LMF) and protein mobilization factor (PMF), in cancerous cachexia is also gaining attention. Third, tumor depletion Reduced energy intake caused by anorexia and/or under-eating, etc., cancer tissue cells themselves also carry out high-consumption energy metabolism, i.e., active through Cori circulation, which increases energy consumption. In addition, protein synthesis increases in actively growing tumor cells, which increases amino acid uptake from the body, and amino acid catabolism in tumor cells is diminished, and patients develop abnormal blood free amino acid profile. As the tumor cells consume large amounts of glutamine, which is mainly stored in the muscle, the myosin synthesis is reduced in the patient.