Whether 2h postprandial blood glucose 9-10mmol/L is harmful to the body needs to be differentiated between normal people and diabetics. If you are a diabetic, 2h postprandial blood glucose 9-10mmol/L is within the control target range. Normal young people fasting blood glucose is 3.9-6.1mmol/L, normal people 2 hours after meal blood glucose is recommended to control within 7.8mmol/L, diabetic patients can be 2 hours after meal blood glucose control below 10mmol/L. Long-term poor blood glucose control may have certain damage to the body, poor blood glucose control is easy to cause atherosclerosis and diabetic peripheral neuropathy and so on. Atherosclerosis mainly includes macrovascular sclerosis and microvascular sclerosis. Macrovascular sclerosis mainly includes carotid arteriosclerosis, aortic arteriosclerosis, coronary arteriosclerosis, cerebral arteriosclerosis, renal arteries and arteries of the lower limbs, etc.; microvascular sclerosis mainly includes arteriosclerosis of the fundus arteriosus and arteriosclerosis of the kidney. Poor glycemic control can also lead to diabetic peripheral neuropathy. This includes numbness or painful lesions in both upper and lower extremities. It is recommended that people with high blood glucose consult an endocrinologist for treatment under the guidance of a doctor.