Fasting hyperglycemia is relatively common among diabetic patients, which may be related to excessive dinner, insufficient dosage of hypoglycemic drugs, nocturnal hypoglycemia, etc. It needs to be treated according to different etiologies, such as changing dietary habits and adjusting medications. 1. Excessive dinner: If dinner is eaten too late or too full, it can lead to an increase in blood glucose after dinner and before bedtime, further affecting fasting blood glucose. You can adjust the dinner not to eat too late, too full, and exercise appropriately after the meal to reduce fasting blood glucose. 2. Insufficient dosage of hypoglycemic drugs: Hypoglycemic drugs are usually used during the day, and by the next morning the effects of many hypoglycemic drugs are significantly weakened, which may lead to fasting hyperglycemia. Drugs should be adjusted under the guidance of the doctor, such as taking metformin before bedtime, or using long-acting insulin therapy before bedtime, which can control fasting hyperglycemia very well. 3. Nocturnal hypoglycemia: Nocturnal hypoglycemia will lead to elevation of glucagon and fasting hyperglycemia in the early morning, which is called Sumuje phenomenon. If there is nocturnal hypoglycemia, the dose of hypoglycemic drugs should be reduced before bedtime and blood glucose monitoring should be performed several times. Fasting hyperglycemia needs to be clarified under the guidance of a doctor to determine the cause and adjust the medication in time.