The ketogenic diet is intended for use in patients with epilepsy whose seizures are resistant to conventional drug therapy. It is a diet high in fat and low in carbohydrate and protein content, and is intended to produce ketosis from the incomplete metabolism of fats. It is safe and effective--many patients with severe, drug-resistant epilepsy show improvement. Limiting carbohydrate intake in patients to obtain the necessary ratio of fats to carbohydrates and protein requires careful planning and, in children, parental involvement. Although the ketogenic diet is professionally planned, an unrecognized source of carbohydrates is prescription and over-the-counter medications. If the carbohydrate content of medications is overlooked, ketosis can be inhibited with potential loss of seizure control occurring. Thus, it is essential for care providers and parents to know the carbohydrate content of medications, including not only the typical sugar content, but also the content of reduced carbohydrate (e.g., glycerin). From information supplied by drug manufacturers, we determined the carbohydrate content of commonly used medications. By knowing the carbohydrate content of these often used medications, the additional carbohydrate content of the medications can be taken into account and adjustments can be made in the ketogenic diet.