The present invention aims to provide ligand agents for peroxisome proliferator-activated receptors (PPARs), etc. The ligand agents of the present invention are characterized by comprising, as an active ingredient, an extract of one or more plants selected from the following: Serenoa repens, Acanthopanax senticosus, Euterpe oleracea, Elettaria cardamomum, Angelica archangelica, Psidium guajava, Prumus spinosa, Eleagnus multiflora, Ligusticum chuaxiong, Cannabis sativa, Sambucus nigra, Adinandra nitida, Passiflora incarnata, Peucedanum japonicum, Pimpinella anisum, Vitex agnus-castus, Withania somnifera, Calluna vulgaris, Crataegus monogyna, Linum usitatissimum, Pleurotus ferulae, Robinia pseudoacacia, and Acanthopanax sessiliflorus.