['UV radiation induces damage to human skin. Protection of skin by an oral photoprotective agent would have substantial benefits. Objective We investigated the photoprotective effect of oral administration of an extract of the natural antioxidant Polypodium leucotomos (PL).', 'A total of 9 healthy participants of skin types II to III were exposed to varying doses of artificial UV radiation without and after oral administration of PL (7.5 mg/kg). At 24 hours after exposure the erythema reaction was assessed and paired biopsy specimens were obtained from PL-treated and untreated skin.', 'A significant decrease in erythema was found in PL-treated skin (P < .01). Histologically, PL-treated biopsy specimens showed less sunburn cells (P < .05), cyclobutane pyrimidine dimers (P < .001), proliferating epidermal cells (P < .001), and dermal mast cell infiltration (P < .05). A trend toward Langerhans cell preservation was seen.'] Does oral Polypodium leucotomos extract decrease ultraviolet-induced damage of human skin?