It is now ten years since the treatment of epilepsy by means of the ketogenic diet was started at the Mayo Clinic. During this period, 369 children up to the age of 14 years have been treated and kept under as close observation as possible by means of written reports from the parents and in many cases by return visits of the patients to the clinic. A report of the progress in these cases was published in 1925,1 19272 and 1930.3 In these reports it was noted that 30 per cent of the patients with idiopathic epilepsy were "cured;" that is, they were free from attacks for one year or more, although they had returned to a normal diet. Approximately 23 per cent were reported improved. As was pointed out in the report of 1930, in the ultimate analysis these cases must be considered failures, but the