en عمومى General پژوهشي Research <p><strong>Background:</strong><em> Mentha longifolia</em> is one of the aromatic medicinal plant belongs to Lamiaceae family. There are some active ingredients in the essential oil of<em> M. longifolia</em>, which potentially could impair the hepatic function. The aim of this study was to find the maximum dose of essential oil<em> of M. longifolia </em>(EOML) that does not show any hepatic deterioration.</p> <p><strong>Methods:</strong> Adult Wistar rats fed different doses of EOML as 50, 100, 200, 300, 400or 600 mg/kg, for two wk. After the completion of administration, the serum activity of ALT, AST, and ALPas the well-known liver toxicity enzymes and the serum total billirubine were measured, by spectrophotometer. The study was done at 2016 in Isfahan Pharmacy School, Isfahan, Iran.</p> <p><strong>Results:</strong> Totally, 400 mg/kg of EOML significantly raised all of the evaluating factors compare to the control group. We found complete mortality in animals that received 600 mg/kg of EOML.</p> <p><strong>Conclusion:</strong> The essential oil of <em>M. longifolia </em>is not entirely safe especially for the liver. Administration at the dose of 400 mg/kg leads to the hepatotoxic effect. The death occurred in the higher doses. The possible mechanisms for the EOML liver toxicity are triggering of oxidative stress or apoptosis by its ingredient like pulegone compound.</p> Essential Oil, Hepatotoxic Effect, Mentha Longifolia, Safety 7 13 http://ijt.arakmu.ac.ir/browse.php?a_code=A-10-390-2&slc_lang=en&sid=1 Mohammad Hossein Hesami 10031947532846006517 10031947532846006517 No Department of Pharmacology and Toxicology, Isfahan University of Medical Sciences, Isfahan, Iran. Seyed Ebrahim Sajjadi 10031947532846006518 10031947532846006518 No Department of Pharmacology, Isfahan University of Medical Sciences, Isfahan, Iran. Ali Hosseini-Sharifabad hosseini_a@pharm.mui.ac.ir 10031947532846006519 10031947532846006519 Yes Department of Pharmacology and Toxicology, Isfahan University of Medical Sciences, Isfahan, Iran.