Thirteen children with refractory epilepsy received a ketogenic diet (medium chain triglyceride oil diet) as an alternative therapy since September 1997. Their seizure patterns included (1) generalized tonic-clonic seizures, (2) myoclonic seizures, (3) generalized tonic + atonic seizures, (4) complex partial seizures, (5) generalized clonic + atonic + myoclonic seizures, (6) head nodding + myoclonic + gelastic seizures, and (7) generalized tonic-clonic + myoclonic + atonic seizures. Major concerns emphasized on the efficacy and side effects of the diet. Clinical observation one month after the diet revealed that 53.8% of the patients had a > 75% reduction in seizure frequency and 76.9% of the patients had a > 50% reduction in seizure frequency. Six patients had some degrees of improvement in cognitive function and/ or school performances. The most common side effects were body weight loss (n = 6) and diarrhea (n = 5). Others included bad temper (n = 1), abdominal cramps (n = 2), nausea (n = 2), bad body smell (n = 1), and renal stones (n = 1). Even after discontinuation of the diet, 61.5% of patients still had a > 50% reduction in seizure frequency. We concluded that the ketogenic diet deserves a trial in children with refractory epilepsy.