Nervous system damage caused by diabetes mellitus is complex and varied, and can invade the brain, spinal cord and peripheral nerves, etc. Symptoms can be manifested as abnormal sensation of limbs, itchy skin, diarrhea, etc. It is recommended to consult a doctor. 1. Peripheral nerves: Due to unsatisfactory blood sugar control, the peripheral nerves are affected. Burning sensation, pins and needles sensation and electric shock sensation in the lower limbs may occur, which is heavy at night, and sometimes the pain is so severe that it is hard to bear and affects sleep. There can also be numbness of the limbs, ants sensation and other sensory abnormalities, improve after activities, there can be glove – sock-like sensory hyperalgesia or allergy. 2. Autonomic nerves: Due to unsatisfactory glycemic control, the autonomic nerves are affected. Clinical manifestations may include delayed gastric emptying, diarrhea and constipation after meals. It is recommended that diabetic patients follow the doctor’s instructions for treatment, not to reduce or increase the dosage of medication by themselves, and go to the hospital in time when other discomforts occur, so as to avoid delaying the condition.