Cerebrospinal fluid (CSF) markers of cerebral energy depletion were measured in 32 infants and children following short (less than 10 minutes) febrile convulsions, and in 19 controls. Specific and sensitive indices of high-energy phosphate compound depletion (hypoxanthine, xanthine and uridine) showed no marked changes. Values for patients and febrile controls were significantly higher than for afebrile controls, which is consistent with increased cerebral metabolism in febrile patients. There were no differences in pH, lactate or creatine kinase levels in the CSF of patients and controls. The results suggest that short febrile convulsions are benign and that in the absence of risk factors for the subsequent development of epilepsy, prophylactic anticonvulsant treatment is not indicated.