Diabetes mellitus is a group of metabolic disorders characterized by hyperglycemia. Hyperglycemia, on the other hand, is caused by defective insulin secretion or its impaired biological action, or both. The prolonged hyperglycemia present in diabetes leads to chronic damage and dysfunction of various tissues, especially the eyes, kidneys, heart, blood vessels, and nerves. Complications: 1, diabetic retinopathy Long-term high blood sugar environment will damage the endothelium of retinal blood vessels, causing a series of fundus lesions, such as microangiomas, hard exudates, cotton wool spots, neovascularization, vitreous proliferation and even retinal detachment. General diabetes appear more than ten years of patients began to appear fundus lesions, but if poor glycemic control, or insulin-dependent diabetes mellitus patients may appear earlier fundus lesions, so patients with diabetes mellitus need to regular ophthalmologic examination to check the fundus. 2.Diabetic nephropathy Diabetic nephropathy can be divided into five stages, which may eventually lead to kidney failure. 3.Diabetic foot In the early stage, it is difficult to heal the wound on the foot, if not handled properly, it may lead to amputation. 4, diabetic mouth ulcers Diabetic patients with oral disease is about 2 to 3 times the normal oral disease. Gastric diversion for the treatment of diabetes: diabetes is caused by two reasons, one, in the gastrointestinal distribution of K-cells stimulated by food secretion of insulin resistance factor, so that the body produces insulin resistance. Secondly, the islet cells are damaged and apoptotic under the action of insulin resistance factor. The reason why gastric diversion surgery is able to treat diabetes and achieve clinical cure at one time is that the unique feature of gastric diversion surgery is that it changes the physiological flow of food, which is accomplished through the steps of gastric blockage, gastrointestinal anastomosis, and intestinal-intestinal anastomosis. After the surgery, the insulin resistance of the patient’s body is eliminated, and the way the food flows through the body after the surgery also promotes insulin secretion in the patient’s body, reduces apoptosis and proliferation of pancreatic islet cells, restores the function of pancreatic islets, and cures the diabetes mellitus. In addition to the normalization of blood glucose, a series of complications associated with the patient has been well recovered. For example, retinopathy, diabetic nephropathy, diabetic dermatitis, diabetic sexual dysfunction, hypertension, hyperlipidemia and so on are gradually cured. The occurrence of serious complications is eliminated, and the occurrence of disability and death is avoided.