Adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine, uric acid, and pyrimidines bases were determined in cerebrospinal fluid (CSF) of 52 children after simple febrile seizures and in a control group of 63 children. There was no statistically significant difference between the two groups for any of these metabolites, suggesting that simple febrile seizures (SFS) neither significantly disturb the metabolism of nucleotides, nucleosides, or bases nor significantly deplete neuron adenosine ATP levels. Therefore, they do not appear to constitute a threat of neuronal damage.