Ketoprofen has been reported to have such side effects as photosensitive dermatitis in humans (The Ministry of Health, Labour and Welfare, 2001). In the present study, as part of a safety evaluation of Miltax, an application drug containing ketoprofen, phototoxicity of Miltax was examined in guinea pigs. In the present skin phototoxicity study, Miltax was applied for 12 hr. Ultraviolet (UV) rays were irradiated to examine whether or not Miltax elicited skin reaction. Two kinds of UV-A plus UV-B dual irradiation and UV-A single irradiation were used for the elicitation. With UV-A plus UV-B dual irradiation on the Miltax application site, no skin reaction was observed at UV irradiation side in any animals, in contrast to the case of the positive control article, 8-methoxypsoralen (8-MOP). Similar results were obtained with UV-A single irradiation. From these results, Miltax that contained ketoprofen did not show any skin phototoxicity in the guinea pig.