The main effects of hypoglycemia are sympathetic hyperexcitability and brain dysfunction. Hypoglycemia is a group of syndromes caused by a variety of etiologies characterized by low venous plasma glucose concentrations and clinically by sympathetic arousal and cerebral dysfunction. Hypoglycemia leads to the following two effects: 1. Autonomic over-excitation manifests itself in sweating, hunger, abnormal sensation, salivation (drooling), trembling, palpitation (rapid heartbeat, often accompanied by panic), nervousness, anxiety, weakness, pallor, cold extremities, and mild elevation of systolic blood pressure. 2. Brain dysfunction at the initial stage manifests as inattentiveness, slow thinking and speech, dizziness, blurred vision, unsteady gait, drowsiness, and there may be mental symptoms such as irritability, hallucinations, agitation, and even convulsions, coma, and so on. Hypoglycemia is a common complication of diabetes mellitus and is more harmful, attention should be paid to strict control of blood glucose stabilization, treatment under the guidance of the doctor, to avoid the occurrence of hypoglycemia.