Dipropylacetate (DPA) was used in the treatment of different types of epilepsy in 112 children aged 1--20 years, with a mean age of 9.2 years, for a period of 19.8 months, ranging from 1 to 49 months. Of this group, 64 children were therapy-resistant to other antiepileptic medications prior to the introduction of DPA; 31 were treated for the first time with an antiepileptic drug, which was DPA; 44 were treated with DPA alone; and 68 had one or more additional antiepileptic medication. The following results were found while DPA was administered in a relatively high dosage with a mean of 48 mg/kg body weight/day and ranging from 7 to 125 mg/kg/day. 1. Statistically, the results are significantly better in primary generalized epilepsy than in partial or in secondary generalized epilepsy. 2. Ninety-two percent of 51 patients who had absences were treated successfully. The same applies to 87% of 30 patients with primary generalized grand mal with spike wave, to all four patients who had impulsive petit mal, and to 47% of the 15 patients who had centrencephalic myoclonic-astatic petit mal. 3. Positive effect of DPA in partial epilepsy and secondary generalized epilepsy was seen only if the EEG pattern was 'centrencephalic' besides focal changes. During therapy with DPA, five patients with pure focal EEG showed an increase in seizure frequency, which demonstrated complete therapeutic failure. 4. Centrencephalic seizure activity (irregular spike wave, 3/s spike wave, and more than 3.5/s spike wave) were treated successfully (P less than 0.001). Focal changes or focal sharp wave with tendency to spread or generalization were treated unsucessfully.