Activators of peroxisome proliferator-activated receptors comprising a polyprenyl compound, preferably (2E,4E,6E,10E)-3,7,11,15-tetramethyl-2,4,6,10,14-hexadecapentaenoic acid, as an active ingredient, and medicaments for preventive and/or therapeutic treatment of hyperlipidemia, non-insulin dependent diabetes mellitus or the like comprising a polyprenyl compound as an active ingredient.