Nigella sativa (NS), commonly known as black cumin, has been used for medicinal purposes. Traditionally the seeds and its oil are used in several diseases. The greatest part of the remedial properties of this plant is due to the presence of thymoquinone (TQ) which is a major active chemical component of the essential oil. The current study performed to evaluate the effect of Nigella sativa Oil (NSO) extract on the neurotoxic and hepatotoxic potentials from Valproic acid (VPA) administration. Also we summarize recent findings emphasizing the role of main neurotoxic and hepatotoxic markers and oxidative stress in study’s case. Neurotoxicity was induced by VPA at dose of (500 mg/kg b.wt) by gastric intubation daily for 30 day. These rats received NSO extract was given orally at dose of (0.5 ml/kg b.wt) daily for 30 days after VPA administration. The current results revealed that NSO extract treatment ameliorated significantly the elevated levels of the neurotoxic and hepatotoxic biomarkers which elevated as a result to VPA administration. Moreover, NSO extract treatment ameliorated the non-enzymatic antioxidant, brain and liver lipid peroxidation (LPO) and glutathione (GSH) concentration and the enzymatic antioxidant, brain and liver catalase(CAT) activity.