A healthy 18-month-old girl with a nasal tip IH, previously treated with topical clobetasol propionate (at age 2-9 months) was started on propranolol for continued growth of her hemangioma. There was no history of hypoglycemia or other medications. The initial dose of propranolol hydrochloride, 0.5 mg/kg/d, divided and given twice daily, was titrated to 1 mg/kg/d over several weeks. After 2 months there was minimal change in the size of the IH, and the propranolol hydrochloride dosage was increased to 1.25 mg/kg/d, divided and given twice daily. During an intercurrent illness (fever, nausea, vomiting), propranolol was withheld. After 4 days she began eating normally, and propranolol was restarted. The day prior to hospitalization, she ate dinner at 5 PM, had propranolol at 6 PM, and went to bed. The mother found her 13 hours later in bed, cold, clammy, and unresponsive. A 10-minute seizure occurred prior to transport by ambulance to the ED. Her rectal temperature was 35.4°C, her pulse was 84 bpm, and her BP was 98/62 mm Hg. Thirty minutes after arrival, she had another seizure and was given lorazepam. Her blood glucose level was 19 mg/dL, her serum glucose level was 24 mg/dL, and her urine ketones level was 15 mg/dL. She was given 9 mL of a 25% dextrose solution intravenously, which resulted in normalization of her glucose level. She was admitted to the hospital and had no further episodes of hypoglycemia or seizures for the next 48 hours (fingerstick glucose level checked every 2-4 hours). Her organic and amino acid levels were normal.