In order to investigate the potential of Platycarya strobilacea fruit extract as an active ingredient for cosmetics, we measured their free-radical scavenging activity, elastase inhibitory activity, the expression of MMP-1 (matrix metalloproteinase-1), and type I collagen synthesis in normal human fibroblast cells. To isolate the main component compounds from P. strobilacea fruit extract, we purified the extract through solvent fractionation, column chromatography, and recrystallization. The component compounds were identified as ellagic acid and 4-O-xyloside of ellagic acid (ellagic acid 4-O-xylopyranoside). P. strobilacea fruit extract and ellagic acid increased the expression of type I collagen mRNA in a dose-dependent manner (up to 37% and 41% at 20 microg/ml and 1.0 microg/ml, respectively), comparable to that of ascorbic acid (up to 39% at 500 muM). A clinical study of measurements using visual evaluation and image analysis showed a statistically significant difference (p < 0.05) between the effects of the test and placebo products. This result suggests that P. strobilacea fruit extract could be used as an active ingredient for antiaging cosmetics.