Severe hypoglycemia leading to permanent brain damage is rare in non-diabetic population. We present one case where chronic alcoholism combined with prolonged fasting lead to such a state. A 51-year-old male patient, a chronic alcoholic, was found unconscious and brought to the emergency room. At the time of hospitalization, consciousness was stupor and he had a blood glucose of 5 mg/dl and MRI of the brain showed high signal density of the inner temporal gyrus and both hippocampus in T2 weighted imaging. There was no history of diabetes. After two months of rehabilitation, improvements were showed to Rancho Los Amigos recognition scale IV, fair grade of muscular strength in upper and lower limbs, FIM score of 21, and dysphagia was improved and nutrition supply was intaken orally. An alcoholic for a long period of time without adequate nutrient supply was experienced to develop into hypoglycemic encephalopathy and therefore reported.