Chemotherapy and radiotherapy are among the traditional methods used in cancer treatment and they cause toxicity to normal cells. The purpose of the present study is to determine the possible protective role of Nigella sativa seed (2 g/kg) extract as a potent antioxidant in improving the toxicity of doxorubicin (DOX) and/or gamma radiation in albino rats. The rats were injected with DOX (2.5 mg/kg, i.p.) and/or exposed the rats to irradiation (2 Gy, whole-body) weekly, for four consecutive weeks. The antioxidant treatments were used daily via oral gavages for two weeks protection period and during the experiment (4 weeks). The DOX and/or irradiated groups recorded a severe reduction of antioxidant parameters (superoxide dismutase, catalase and reduced glutathione) as well as increased thiobarbituric acid reactive substances, and changes of liver function parameters (transaminases, alkaline phosphatase, total protein and albumin as compared with control rats. Administration of Nigella sativa seed extract to DOX and/or irradiated rats indicates significantly enhanced the oxidative stress markers and liver function parameters as compared with DOX and/or irradiated rats.
          In conclusion, Nigella sativa seed extract fruit extract used to decrease the bad side effects of chemotherapy and radiotherapy.