A 2-hour postprandial glucose is lower than a fasting glucose and should be judged in relation to a specific blood glucose value. Common causes include the Sumuje reaction, dawn phenomenon, and medications. It is important to choose the targeted treatment according to the cause. 1. Sumuje reaction: refers to the phenomenon of low blood glucose at night and high blood glucose in early morning fasting. This is because of the nighttime hypoglycemia, the body through the feedback regulation mechanism, so that the hormone secretion that can raise blood glucose increases, resulting in early morning blood glucose rebound elevation. You should pay attention to the nocturnal hypoglycemia and adjust the time of using hypoglycemic drugs and insulin and the dosage before bedtime. 2. Dawn phenomenon: It refers to the situation that blood glucose is controlled within the normal range at night, and in the absence of hypoglycemia at night, the secretion of glucagon before and after dawn leads to the increase of fasting blood glucose in the early morning. For people with dawn phenomenon, they should avoid omitting regular meals and consume carbohydrates before going to bed. 3. Medications: Improper use of oral hypoglycemic drugs or insulin can lead to low blood glucose 2 hours after meal or high fasting blood glucose, it is recommended to consult a doctor to adjust the medication. When blood glucose is abnormal, you should consult a doctor and standardize the use of medication under the doctor’s guidance to slow down the progression of the disease.