Early stage of diabetes mellitus is characterized by the metabolic disorder symptoms of “three more and one less”, i.e. polyuria, polydipsia, polyphagia and emaciation. However, there are also many patients who do not have any symptoms and are diagnosed with diabetes after finding elevated blood glucose during physical examination. 1. Polyuria, polydipsia: elevated blood glucose causes polyuria due to osmotic diuresis, followed by thirst and polydipsia. 2. Eating more: diabetic patients will stimulate the secretion of insulin in high blood glucose, usually feel hungry more easily than normal people, and will eat more uncontrollably. 3. Weight loss: elevated blood glucose, glucose utilization disorders appear lipid, protein metabolism abnormalities, resulting in patients with malnutrition, wasting, children’s growth and development is impaired. Diabetes mellitus is a chronic disease that can cause heart and kidney complications, and requires long-term compliance with medication, as well as dietary control and active exercise in daily life. Diabetes can be asymptomatic in the early stages and requires vigilance. Regular checkups are recommended for early diagnosis and early treatment under the guidance of a doctor.