High blood glucose 4 hours after meal is usually caused by diabetes, irrational diet structure and other reasons. 1. Diabetes mellitus: Diabetes mellitus refers to a significant increase in blood glucose in the human body, usually due to genetic factors, environmental and other reasons, there will be a loss of weight, blood glucose, and other symptoms, thus resulting in a high blood glucose 4 hours after a meal. 2. Irrational diet structure: If the patient’s diet structure is mainly high sugar food or eating too much, it may also lead to 4 hours postprandial high blood sugar. For patients with high blood glucose 4 hours after meal, it is recommended to go to the hospital for examination in time, and it is recommended to conduct intravenous fasting blood glucose, blood glucose 2 hours after meal under the guidance of the doctor, and cooperate with the doctor for active treatment.