In order to investigate a potential anticonvulsive action of sertraline (i.p.), its effects on seizures, EEG epileptiform activity and EEG amplitude increases induced by two convulsive agents were evaluated and compared with the effects of carbamazepine. Around 20. min following 4-aminopyridine (4-AP, 2.5. mg/kg, i.p.), tonic-clonic seizures and epileptiform activity were observed in control animals. A single sertraline pre-injection of 2.5. mg/kg, but not of 0.75. mg/kg, prevented these changes to 4-AP. Repeated daily administration of 0.75. mg/kg for one week, however, effectively inhibited the changes induced by 4-AP. The first generalized tonic-clonic seizure and EEG changes in response to pentylenetetrazole (PTZ, 50. mg/kg, i.p.) were observed near the first minute in control animals. Single sertraline doses above 5. mg/kg prevented the PTZ-induced changes. Moreover, a single carbamazepine dose of 25. mg/kg (i.p.), but not of 15. mg/kg, prevented the changes induced by the above convulsive agents. An anti-seizure action of the antidepressant sertraline is strongly suggested by these findings.