Conventional anti-epileptic treatments have limitations in treating many epileptic patients. Although there have been great advances in the management of epilepsy by application of newly developed anti-convulsants and surgery, some patients still remain in an intractable condition. Other supplementary treatments including immunoglobulin, steroids, and ketogenic diet have significant anti-epileptic potencies. Immunoglobulin treatment shows benefits in some autoimmune-related epileptic conditions such as Rasmussen's encephalitis, however, still has limitations in long-term efficacy. Steroids show significant improvements in many epileptic syndromes including infantile spasm, Lennox-Gastaut syndrome, Landau-Kleffner syndrome, and epilepsy with continuous spikes and waves during slow wave sleep, however, some of them recur during or after tapering of the drug. Ketogenic diet has become one of the most reliable treatments for intractable epilepsy especially in children. Ketogenic diet is difficult to maintain because of poor palatability, but shows a very high anti-epileptic efficacy. These supplementary treatments should be considered in various epileptic conditions especially in intractable patients.