Abstract: Objective To identify the clinical features and pathogenesis of hypoglycemia with brain dysfunctions as the main manifestations. Method A retrospective analysis of 73 cases with brain dysfunctions caused by hypoglycemia was performed. Result Hypoglycemic brain dysfunctions were mainly caused by poor control of the dosage of hypoglycemic agents in diabetic patients, and the major clinical manifestations included coma, hemiparalysis, epilepsy and mental disorders. The pathogenesis was complicated, possibly related to a variety of factors such as rapid declination of blood sugar level, aging, cerebral arteriosclerosis, and hypoglycemic cerebral vasospasm or selective nerve injury. Conclusions A blood sugar test should be performed for any patients with brain dysfunctions of unidentified causes for early diagnosis and treatment. In addition, diabetic patients should take hypoglycemic agent adequately. Regular monitoring of blood sugar level is key to the prevention of hypoglycemia.