Abstract: Background and Objective: Dimethylnitrosamine (DMN) is a representative chemical of a family of N-nitroso compounds and has been found in processed meats and industrial products. Alpha Lipoic Acid (ALA) found naturally in plants and animals is involved in many different antioxidant functions in all body tissues. So, the study was designed to find out the efficacy of ALA in reducing the DMN-toxicity in male mice by measuring some biomarkers functions of liver as well as oxidative stress parameters and histopathological changes. Materials and Methods: Animals were divided into 6 groups (n = 8) and received their treatment for 4 weeks as follows: Groups 1-4 served as control, ALA-treatment (16.12 mg kg^–1), DMN-low dose treatment and DMN-high dose treatment, respectively. Groups 5 and 6 were received ALA before DMN-low and DMN-high dose, respectively. Results: The treatment of the mice with DMN caused significant changes in serum biomarker enzymes of liver, lipid profile, protein content and myeloperoxidase as well as hepatocytes lipid peroxidation, superoxide dismutase, catalase, glutathione peroxidase, nitric oxide, xanthine oxidase and total antioxidant capacity. Histopathological analysis of liver confirmed the oxidative stress results. Conclusion: Concomitant administration of ALA with DMN significantly protected most of the changes induced by DMN suggesting its protective efficacy.