There are many reasons for high blood glucose, such as improper diet, diabetes, infection, stress and other factors may cause elevated blood glucose levels, and when blood glucose is elevated, it is necessary to consult a doctor in a timely manner. Patients with high blood glucose should monitor their fasting blood glucose and 2-hour postprandial blood glucose regularly. Normal people’s fasting blood glucose generally fluctuates between 3.9~6.1mmol/L, and 2-hour postprandial blood glucose is generally below 7.8mmol/L. Eating large amounts of sweets or high-calorie foods may result in elevated blood glucose levels for testing; diabetes is a metabolic disease characterized by chronic hyperglycemia, and therefore elevated blood glucose levels; and blood glucose levels may also be elevated during infections or stressful situations. High blood glucose levels should be detected and treated under the supervision of a medical professional.