The effects of ornithine alpha-ketoglutarate (OKG) on ammonium acetate induced hepatotoxicity were studied in experimental rats. The levels of urea, non-protein nitrogen and thiobarbituric acid reactive substances were significantly increased in ammonium acetate treated rats; but these levels were significantly decreased in ammonium acetate-OKG treated rats. Similar patterns were observed in the levels of free fatty acids, triglycerides and phospholipids. Furthermore, non-enzymatic (reduced glutathione) and enzymatic (glutathione peroxidase, superoxide dismutase and catalase) antioxidants were significantly decreased in ammonium acetate treated rats, when compared with control and were significantly increased in ammonium acetate-OKG treated rats compared to ammonium acetate treatment alone.