Diabetes is a group of metabolic disorders such as protein, fat and electrolytes caused by absolute or relative insufficiency of insulin secretion and reduced sensitivity of target tissue cells to insulin, of which hyperglycemia is the main marker. Diabetes can cause a variety of complications. Serious long-term complications include: cardiovascular disease, chronic renal failure, retinopathy, neuropathy and microangiopathy. Among these, microangiopathy may lead to erectile dysfunction (impotence) as well as difficult wound healing. Difficult-to-heal wounds in the foot can lead to gangrene (commonly known as “diabetic foot”), which can result in amputation. If diabetes is adequately controlled and blood pressure is adequately controlled, combined with good lifestyle habits (e.g., not smoking, maintaining a healthy weight, etc.), the risk of developing these complications can be effectively reduced. Diabetic mouth ulcers: Diabetic patients with oral disease is about 2 to 3 times the normal oral disorders. The incidence of oral disease in male diabetic patients is significantly higher than that of diabetic women. The findings suggest that: diabetes is prone to periodontal disease, and periodontal infection caused by systemic toxicity, and aggravate the condition of diabetes. Patients suffering from these two diseases “sandwiched”, should become the focus of preventive health care. Because high blood glucose levels provide rich nutrition for subgingival bacteria and blockage of gingival tissue microvasculature, the utilization of gingival oxygen is reduced. Diabetic retinopathy: Long-term hyperglycemic environment will damage the endothelium of the retinal vessels, causing a series of fundus lesions, such as microangiomas, hard exudates, cotton wool spots, neovascularization, vitreous proliferation and even retinal detachment. Generally, patients with diabetes for more than ten years start to develop fundus lesions, but if the blood sugar control is poor, or insulin-dependent diabetes patients may develop fundus lesions earlier, so diabetic patients need to go to the ophthalmology examination regularly to check the fundus. Diabetic foot: Initially, it is difficult to heal the foot wound, and if not properly treated, it can lead to amputation. Diabetic nephropathy: Diabetic nephropathy can be divided into five stages, which may eventually lead to kidney failure. Diabetic coma: 1, non-ketotic hyperosmolar coma: this coma is mostly seen in elderly diabetic patients over 60 years old. The main clinical manifestations are severe dehydration, hyperglycemia, high plasma osmolality and neuropsychiatric symptoms. Principles of first aid for diabetic coma: Treat according to the principles of first aid for coma: keep the airway open to prevent accidental aspiration of vomitus. Once respiratory arrest is detected, immediately perform artificial respiration. Call “120” emergency personnel, send the patient to the hospital, first check the blood sugar to determine the direction of treatment. Do not feed sugar water to comatose patients to avoid choking and coughing or even suffocation. 2, hypoglycemic coma: when the blood sugar is lower than 3 mmol / l is called hypoglycemia, serious hypoglycemia will occur coma. The common reasons are: excessive insulin or oral and hypoglycemic drugs and little food; increased exercise but no corresponding increase in food intake. 3, ketoacidosis coma: the causes include the following: diabetic patients with insulin discontinuation or too rapid reduction, or aggravation of the disease; various acute and chronic infections; stress, such as trauma, surgery, childbirth, pregnancy, acute myocardial infarction, hyperthyroidism, etc.; eating disorders, eating too much or too little, excessive alcohol consumption, etc.