We evaluated the use of felbamate in 379 adults and children with refractory epilepsies in an open-label, compassionate clinical use setting. Prior to the termination of the program, because of reports of aplastic anemia, 351 patients had completed 2 months of treatment with felbamate at a dose of 2400-3600 mg/day for adults or 30-45 mg/kg/day for children. Of the 246 patients who had a diagnosis of therapy-refractory localization-related epilepsy with or without secondary generalization, 52% (126/246) achieved a seizure reduction of 50% or more, including 10% (25/246) who became seizure free. There was no difference in response rate between adults and children. Of the 80 patients who had a diagnosis of Lennox-Gastaut syndrome (LGS), 60% (48/80) achieved a seizure reduction of 50% or more, including 6% (5/80) who became seizure free. Of the 25 patients with a diagnosis of generalized epilepsy (other than LGS) or undetermined epilepsy whether focal or generalized, 60% (15/25) achieved a seizure reduction of 50% or more, including 12% (3/24) who became seizure free. The results of this uncontrolled study suggest that felbamate could be useful in patients with epilepsies which are refractory to other antiepileptic drugs after careful risk-benefit assessment and consideration of all circumstances involved.