The present invention provides a compound useful in the prevention and treatment of nonalcoholic fatty liver disease. The invention relates to a drug for the prevention and/or treatment of nonalcoholic fatty liver disease, the drug having as an active ingredient (R)-2-[3-[[N-(benzoxazol-2-yl)-N-3-(4-methoxyphenoxy)propyl]aminomethyl]phenoxy]butyric acid, a salt thereof, or a solvate of these.
