The purpose of the present invention is to provide a prophylactic or therapeutic agent for fatty liver diseases which is effective against non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH), in particular. The present invention relates to a prophylactic or therapeutic agent for fatty liver diseases and is characterized by containing ibudilast as an active ingredient.本發明之目的在於提供一種對於NAFLD、尤其是NASH有效之脂肪性肝疾病之預防或治療劑。本發明係關於一種脂肪性肝疾病之預防或治療劑，其特徵在於含有異丁司特(Ibudilast)作為有效成分。
