Introduction: A relationship between epileptic seizures and brain tissue oxidative damage has been suggested. Ocimum basilicum (O. basilicum) has been shown to have beneficial effects including hypnotic and protective against tissue oxidative damage. The present study was designed to evaluate the effects of O. basilicum hydro-alcoholic extract on oxidative damage of brain tissue following seizures induced by pentylenetetrazole (PTZ) in mice. Methods: The animals were grouped and treated as follows: 1- control group which received saline; 2- PTZ group (90 mg/kg, ip); 3 to 5- three groups which received 25, 50 or 100 mg/kg of a hydro-ethanolic extract of O. basilicum before PTZ. First minimal clonic seizure (MCS) and the first generalized tonic-clonic seizure (GTCS) latencies were analyzed. The brains of the animals were then collected and stored to use for biochemical evaluation. Results: The plant extract in 50 and 100 mg/kg doses, significantly postponed the MCS and GTCS seizures onsets (P<0.05-P<0.01) when administered before PTZ. PTZ - induced seizures also increased lipid-peroxidation in the brain tissue which was presented by a high level of malondialdehyde (MDA) in the brain tissue compared to the control group (P<0.001). O. basilicum extract attenuated MDA levels in the brain (P<0.05-P<0.001). PTZ - induced seizures also decreased brain tissue total thiols compared to the control group (P<0.001). Pretreatment with all doses of O. basilicum extract improved thiol content in the brain tissue (P<0.05). Conclusion: The current study revealed that hydro-ethanolic extract of O. basilicum possesses significant antioxidant and anticonvulsant activities.