Epilepsy is a brain disorder that affects both children and adults. From the 1920s the ketogenic diet has gained prestige as another treatment option for patients with refractory epilepsy.A summary of the evidence will be made through a systematic review of randomized clinical trials that have compared a single ketogenic diet with other diet for the management of these patients.To determine the effectiveness of the ketogenic diet in reducing episodes of seizures in patients with refractory epilepsy. The search strategy included randomized controlled trials and controlled clinical trials. Databases used were Medline, LILACS, Central and CINAHL.Six articles that met our elegibility criteria.There is limited evidence that the ketogenic diet compared to the medium-chain triglyceride diet is more effective in reducing the frequency of seizures. There is also moderate evidence that classical ketogenic diet compared to the gradual diet (2.5:1 and 3:1) is more effective in reducing seizures. There is moderate evidence that classical ketogenic diet compared to Atkins diet is more effective in reducing the frequency of seizure. The decision to apply this type of diet should also be based on costs, preferences and safety of treatment. It should also take into account the likelihood that studies have indexing problems have been left out of the review.