Ketogenic diet is a diet high in fat and low in protein and carbohydrates. It is mainly used for the treatment of refractory epilepsy in children, and its clinical efficacy and side effects are small, but the mechanism of action is still unclear. Ketogenic diet is a diet high in fat, low in protein and low in carbohydrates, which was first designed to mimic the state of ketosis during starvation. It is mainly used to treat refractory epilepsy in children but also for the treatment of glucosyltransferase (GLUT1) deficiency and pyruvate hydrogenase (PDH) deficiency disease, among others. Prohibited disorders include fat oxidation defects, ketone body production and catabolism defects, pyruvate carboxylase deficiency, severe liver disease and certain mitochondrial diseases. Also this diet is associated with short-term complications such as drowsiness, fatigue, gastrointestinal reactions, excessive ketosis and acidosis, and hypoglycemia in some children, and long-term complications such as hyperlipidemia, kidney stones, hypoproteinemia, and growth retardation. The traditional KD fat to protein plus carbohydrate weight is 4:1 . The diet has been adopted by most of the antiepileptic centers in China for the treatment of refractory epilepsy, including some syndromes that are refractory once diagnosed such as Rasmussen’s encephalopathy, tuberous sclerosis, Otahara syndrome, infantile spasms, Lennox-Gastaut syndrome, etc.