Due to the high sensitivity of the disease and few studies in this field, the object of this study was to compare the effect of Orlistat and Metformin in the treatment of fatty liver disease in patients without diabetes mellitus. The method: This study was designed for 12 to 15 weeks and clinical trial. 100 non-diabetic patients with fatty liver disease were referred to Imam Khomeini hospital clinics, are selected. Patients are divided into 2 groups A and B. Group A are patients that 50 people will be prescribed Metformin and that 50 people are in Group B will be prescribed Orlistat. Vitamins or other nutrients will not be prescribed. Considered in all patients (demographic, etc.) Will respond. Blood samples will be collected before and after treatment. Also patients before and after treatment will be examined by ultrasound sonographer. Ultrasound study, each patient before and after each patient by a sonographer and the tests will be carried out by a laboratory center. Eventually the two groups in terms of improving liver function checked. The two groups were compared in terms of better grade. Inclusion criteria for the study: Having Nonalcoholic fatty liver disease, the absence of diabetes mellitus, Fatty liver grade 2 and above, not having severe systemic disease, Lack of viral and autoimmune hepatitis, Lack of thyroid disease, do not have hyper triglyceridemia. Exclusion criteria: Having severe systemic disease, having viral hepatitis and autoimmune, having thyroid disease, Hyper triglyceridemia