Background: There is a great realization that the use of herbs has been considered for the treatment of human diseases such as heptotoxicity and nephrotoxicty since ancient times. Nigella sativa (NS) is one of the most important medicinal plants having strong antioxidant properties. Objectives: Study the possible curative effect of Nigella sativa linn (NSL) oil on experimentally acetaminophen-induced hepatotoxicity and nephrotoxicity in adult male albino rats. Materials and Methods: Fifty adult male albino rats of local strain were chosen as an animal model for this study. They were divided into five equal groups: Negative control group, Positive control group, NsL oil group, Acetaminophen-treated group and Acetaminophen + NsL oil-treated group. Heptotoxicity and nephrotoxicty was induced by oral administration of acetaminophen. At the end of the experiment (24 days), blood samples were obtained for measuring of liver functions (ALT, AST and total bilirubin), kidney functions (serum creatinine and blood urea) and TNFα. Animals were sacrificed; livers and kidneys were obtained for histopathological examination, immunofluorescence analysis for Tansforming Growth Factor-β (TGF-β) and measurement of tissue level of malondialdehyde (MDA) in both liver and kidney.  Results: Acetaminophen-treated group and Acetaminophen + NsL oil-treated group showed significant increases in ALT, AST, total bilirubin serum creatinine,urea, TNFα and tissue MDA in both liver and kidney compared to Negative control group and Positive control group. Acetaminophen+NsL oil-treated group, when compared to Acetaminophen-treated group, showed a significant decrease in all previous parameters. Histopathological examination revealed appearance of partial improvement and evidence of some regeneration of both liver and kidney tissues of Acetaminophen + NsL oil-treated group in comparison with Acetaminophen-treated group in addition to immunofluorescence staining of expression of TGFβ in hepatocytes was improved in Acetaminophen + NsL oil-treated compared to Acetaminophen treated group, but there was no difference in the immunofluorescence staining of kidney sections of the previous groups. Conclusion: Nigella sativa linn oil has a curative role in regeneration of liver and kidney tissues in acetaminophen-induced hepatotoxicity and nephrotoxicity.