The present invention relates to a method for preventing, improving or treating fatty liver by administering an effective amount of azelaic acid to a subject. Azelaic acid is a compound primarily contained in a natural product, has no or fewer side effects and an effect of reducing the degree of accumulation of triglycerides in liver tissue, and thus may be used in treatment and improvement of non-alcoholic fatty liver. In addition, due to an anti-inflammatory effect, azelaic acid may be used in the treatment of steatohepatitis. Therefore, the azelaic acid according to the present invention is expected to be effectively used in food material, drug composition and a health functional food to treat fatty liver or steatohepatitis.
