In a clinical trial study, the therapeutic effect of Melatonin, Metformin and Vitamin E in patients with non-alcoholic fatty liver disease (NAFLD) dietary regimen are assessed. Participants were adults with NAFLD diagnosed by increased alanine aminotransferase (ALT), Aspartate Aminotransferase (AST) and liver ultrasound who did not have other liver diseases, including viral (hepatitis B or C), autoimmune hepititis and genetic conditions (hemochromatosis) or other liver disorders. At the first, the weight, height and waist and hip circumferences and biochemical blood serum assessment including blood sugar 2 hours after food (BS 2hpp), gamma-glutamyl transferase (GGT), Ceruloplasmin, Alkaline phosphatase (ALKP), C-reactive protein (CRP), factors of ALT, AST, fasting blood sugar (FBS), hemoglobin A1C, triglyceride (TG), Total Cholesterol, Ferritin are measured. Patients are randomly placed to three groups by sealed envelop method. One group will be received Melatonin tablet (10 mg) once a day for 30 minutes before sleep with their diet regiment for a period of 3 months. The second group will be received Metformin tablet (500 mg) once a day with their diet for a period of 3 months. The third group will be received Vitamin E tablet (800 IU, natural form) once a day with their diet for a period of 3 months. Patients are followed according to the scheduling program for a period of 3 months, and taking the correct medication, side effects, loss of individual samples and unwillingness to continue treatment are examined. After three months of intervention, measuring weight, waist, hip circumferences and biochemical blood serum test are performed again.