The present invention relates to a novel use of rhododendrin, and more particularly to a composition for antioxidant purposes or for the prevention or treatment of hyperproliferative skin disorders, which comprises rhododendrin as an active ingredient and a method for inhibiting reactive oxygen species or for preventing and treating a hyperproliferative skin disorder, which comprises administering an effective amount of rhododendrin to a subject in need thereof. Rhododendrin is not cytotoxic and has an excellent effect of eliminating a large amount of reactive oxygen species (ROS) generated by TNF-α/IFN-γ or UV light, and thus is effectively used to prepare an antioxidant cosmetic composition or an antioxidant food composition. In addition, rhododendrin has the effect of inhibiting skin cell hyperproliferation and has an excellent effect of inhibiting a hyperproliferative skin disorder or skin hyperkeratinization mediated by Toll-like receptors (TLRs) in various skin diseases, particularly psoriasis.