BACKGROUND The aim of this study was to evaluate the effects of Nigella sativa (N. sativa) oil (NSO) on ovarian oxidative damage following ischemia-reperfusion injury, using a rat model of ovarian torsion. MATERIAL AND METHODS Forty-eight female albino Wistar rats were divided into six groups: (Group 1) laparotomy only; (Group 2) intraperitoneal NSO (2 ml/kg), 1 hour following laparotomy; (Group 3) 3 hours of ovarian ischemia; (Group 4) 3 hours of ovarian ischemia followed by 3 hours of reperfusion; (Group 5) 3 hours of ovarian ischemia and 2 ml/kg of NSO 1 hour before laparotomy; (Group 6) 3 hours of reperfusion after 3 hours of ovarian ischemia and 2 ml/mg of NSO 1 hour before laparotomy. RESULTS The antioxidant status, ceruloplasmin level, native thiol, total thiol, and disulfide levels of the control group (Group 1) were significantly increased compared with the ovarian ischemia-reperfusion group treated with NSO (Group 6) (p=0.003, p=0.002, p=0.006, p=0.001 and p=0.003, respectively); these levels in the ovarian ischemia group (Group 3) and ischemia-reperfusion group (Group 4) were statistically similar to those of the ovarian ischemia + NSO group (Group 5) and ovarian ischemia-reperfusion + NSO group (Group 6). CONCLUSIONS In this preliminary rat study, administration of NSO shortly after the onset of ovarian ischemia-reperfusion injury, did not significantly reduce levels of markers of oxidative injury. Further studies are required to evaluate the ovarian changes at the tissue level, and to determine the optimum dose of NSO.