The aim of the study is to alleviate the symptoms of fatty liver disease. This study is a randomized (through Sealed envelope method), double-blind clinical trial consisted of 44 men and women suffering from non-alcoholic fatty liver disease (22 patients in each treatment and placebo group). Patients with pregnancy and lactation, liver transplantation, rapid weight loss, diabetes and thyroid problems and patients who use medications such as corticosteroids or receive total parenteral nutrition are excluded. The intervention group will receive Black Seed Oil, one capsule (1000 mg) a day after lunch for 2 months. The control group will receive Paraffin oil, one capsule (1000mg) each day after lunch for 2 months. Patients will be followed up every 2 weeks. At the beginning and at the end of the study, blood sample will be taken from the patients after 12-14 hours fasting period. the primary outcomes of the study are inflammatory markers including IL-6, TNF-α, HS-CRP; fasting blood glucose (FBS ), insulin level, liver enzymes (ALT, AST, GGT); total cholesterol (TC); high-density lipoprotein (HDL-C) and triglycerides (TG) and low density lipoproteins (LDL-C) will be calculated. The secondary outcomes of the study are Anthropometric measurements, systolic blood pressure (SBP), diastolic (DBP), diet and physical activity.