PURPOSE: Concentrations of prostaglandin(PG) in the central nervous system is very low in physiologic conditions and are known to increase in response to febrile convulsions. And, intracerebroventricular injection of prostaglandin E-2(PGE) in unanesthetized cats is accompanied by a rise in body temperature, a decrease in convulsions, and a modulation of the convulsive thresholds, but the possible physiological role of different PGs in induction, termination, and recurrences of seizure activity is not clear. We observed the change of PGE according to temperatures in first febrile convulsions, and the relationship between the recurrence of febrile convulsions and PGE. METHOD: In the present study, the body temperatures of patients with initial febrile convulsions were measured. Spinal taps were performed. All CSF samples were stored in a deep freezer at 30degrees C until the time of analysis and tested by Prostaglandin E2 [125I] assay system, Biotra Assays, Amersham Inc. Most children were treated with antipyretics immediately and tepid water massage. 105 patients with febrile convulsions could be studied for 36 months and the times of recurrence after first febrile convulsion during those period were measured. During febrile convulsions, no anticonvulsants were used. Based on 105 children with febrile convulsions, we analyzed the results. RESULTS: The results were as follows : The levels of PGE at temperature 38.4 degrees C, 38.5 degrees C temperature 39.4 degrees C, and temperature 39.5 degrees C were 27.7+/-21.0 pg/mL, 83.6+/-38.3 pg/mL, and 205.6+/-40.0 pg/mL. The levels of PGE during 3 months recurrence group were 79.1+/-15.8 pg/mL, those during 4-6 months recurrence group were 134.9+/-74.6 pg/mL, those during 7-9 months recurrence group were 118.9+/-39.9 pg/mL, those during 10-12 months recurrence group were 133.5+/-69.2 pg/mL, those during 13-18 months recurrence group were 106.5+/-106.4 pg/mL, those during 19-24 months recurrence group were 123.7+/-100.6 pg/mL, and those during 25-36 months recurrence group were 142.1+/-172.5 pg/mL. CONCLUSION: Significantly elevated concentrations of PGE in febrile convulsions were found and related to increased body temperature. In the recurrent groups of febrile convulsions, there was no relationship between PGE levels and recurrences time of febrile convulsions. It is not clear that increased PGE levels are, at least in part, to be related to recurrences of febrile convulsions. We think that more comprehensive research is needed to clarify the role of increased PGE in first febrile convulsion and the relationship to recurrences of febrile convulsions.