Red Ginseng (the roots of Panax ginseng C.A. Meyer) is used clinically in China, Korea and Japan for various diseases, including atherosclerosis, hypertension and stress etc. Although Red Ginseng roots have traditionally been thought to have antiageing effects, the basis for this hearsay is unclear. This study examined the effects of Red Ginseng extract on ultraviolet B (UVB)-irradiated skin ageing in mice. Oral administration of Red Ginseng extract (20 or 60 mg/kg, twice daily) prevented UVB-irradiated skin damage (increases of skin thickness and pigmentation, and reduction of skin elasticity). Furthermore, Red Ginseng extract inhibited the increases of epidermis and corium thickness induced by UVB irradiation. Red Ginseng extract inhibited the increase of skin TGF-beta1 content induced by UVB irradiation. These findings suggest that the protective action of Red Ginseng extract against UVB-irradiated skin ageing may be due partly to an inhibition of the increase of skin TGF-beta1 induced by UVB irradiation. In conclusion, the oral administration of Red Ginseng extract may be useful as a health supplement for protection against photoageing.