The ketogenic diet (KD) is an increasingly recognized treatment for drug-resistant epilepsy, particularly in children and adolescents. Despite the availability of antiepileptic drugs, up to 30–40% of epilepsy patients remain treatment-resistant, leading to decreased quality of life and increased risk of death. The KD, a high-fat, low-carbohydrate diet, has been shown to reduce seizure frequency by over 90% in well-qualified patients. Various forms of the KD, including the classic ketogenic diet (cKD), medium-chain triglyceride (MCT) diet, modified Atkins diet (MAD), and low glycemic index treatment (LGIT), are available. The cKD, with a 4:1 or 3:1 fat-to-protein-carbohydrate ratio, is the most prescribed, followed by the MAD and MCT diets. The LGIT restricts daily carbohydrate intake to 40–60 g. The KD's mechanisms of action include increased ketone bodies, which hyperpolarize neurons and reduce excitability, as well as other factors like neurotransmitter regulation and mitochondrial function improvement. Clinical studies show that the KD can achieve seizure freedom in up to 8.4% of children and a ≥50% reduction in seizure frequency in 61.4–72% of patients. Adverse effects are generally mild and controllable, though long-term use may lead to dehydration, gastrointestinal issues, and metabolic disturbances. The KD is contraindicated in patients with lipid and pyruvate metabolism errors. Overall, the KD is a promising treatment for drug-resistant epilepsy, especially in younger patients, but more research is needed to confirm its long-term efficacy and safety.The ketogenic diet (KD) is an increasingly recognized treatment for drug-resistant epilepsy, particularly in children and adolescents. Despite the availability of antiepileptic drugs, up to 30–40% of epilepsy patients remain treatment-resistant, leading to decreased quality of life and increased risk of death. The KD, a high-fat, low-carbohydrate diet, has been shown to reduce seizure frequency by over 90% in well-qualified patients. Various forms of the KD, including the classic ketogenic diet (cKD), medium-chain triglyceride (MCT) diet, modified Atkins diet (MAD), and low glycemic index treatment (LGIT), are available. The cKD, with a 4:1 or 3:1 fat-to-protein-carbohydrate ratio, is the most prescribed, followed by the MAD and MCT diets. The LGIT restricts daily carbohydrate intake to 40–60 g. The KD's mechanisms of action include increased ketone bodies, which hyperpolarize neurons and reduce excitability, as well as other factors like neurotransmitter regulation and mitochondrial function improvement. Clinical studies show that the KD can achieve seizure freedom in up to 8.4% of children and a ≥50% reduction in seizure frequency in 61.4–72% of patients. Adverse effects are generally mild and controllable, though long-term use may lead to dehydration, gastrointestinal issues, and metabolic disturbances. The KD is contraindicated in patients with lipid and pyruvate metabolism errors. Overall, the KD is a promising treatment for drug-resistant epilepsy, especially in younger patients, but more research is needed to confirm its long-term efficacy and safety.