In vivo studies were carried out to decide how vitamin E (dl. a-tocopherol acetate) and Nigella sativa seeds administrated orally combined with or without the deep fat frying (over heated oil) influence the glutathione dependent enzymes [(glutathione peroxidase (GP-ase), Glutathione reductase, (G-R-ase) and Glutathione transferase, (G-S-ase)), as well as reduced glutathione (GSH), Hydroxyl radical (OH) and lipid peroxidation (LP) of rat liver. It was found that, both vit. E and N.sativa seeds influence the action of deep fried fat but they are not able fully to prevent or eliminate its toxic effects.