Malabsorption syndrome is a syndrome caused by various causes of malabsorption of nutrients from the small intestine, the absorption of which must undergo adequate digestion. Malabsorption syndrome causes a series of pathophysiological changes due to impaired absorption of nutrients, vitamins and electrolytes. The main clinical manifestations are: 1, diarrhea and other gastrointestinal symptoms Diarrhea is the main symptom, and the most characteristic. Defecation 3-4 times a day or more, fecal volume, unshaped, light-colored with grease-like gloss or foam, with bad odor. It can also be watery diarrhea. A small number of mild or atypical cases may be without diarrhea. It is accompanied by abdominal rumbling, bloating, abdominal discomfort, but rarely abdominal pain. Some patients may have loss of appetite and nausea, vomiting. 2.Nutritional deficiency symptoms After the occurrence of diarrhea, due to protein loss and insufficient supply of heat, patients gradually feel weakness, emaciation, weight loss, may appear anemia, swelling of the lower limbs, hypoproteinemia. 3. Symptoms of vitamin and electrolyte deficiencies Symptoms of various vitamin deficiencies or electrolyte deficiencies may occur to varying degrees. Such as vitamin D and calcium absorption disorders can have bone pain, hand and foot convulsions, and even pathological fractures; vitamin B malabsorption can appear tongue inflammation, stomatitis, peripheral neuritis, etc.; vitamin B12 folic acid and iron malabsorption can cause anemia; insufficient potassium ion supplementation can aggravate weakness, weakness, physiological oliguria, nocturia, etc. Secondary malabsorption syndrome in addition to the above malabsorption manifestations, but also has the original manifestation. Diagnosis: This disease should be differentiated mainly from tuberculous peritonitis, megacolon and food intolerance. The possibility of malabsorption should be considered in patients with chronic diarrhea and weight loss, especially in patients with steatorrhea. In addition, patients who have undergone partial esophagectomy, esophagogastrectomy, total gastrectomy, partial gastrectomy, vagotomy, small bowel resection, etc., patients with pancreatic hypoplasia, hepatobiliary disease, blind loop syndrome and other small bowel lesions requiring surgery may have malabsorption syndrome.