Two new polyacetylenes, oploxynes A (1) and B (2), and the known oplopandiol (3) and falcarindiol (4) were isolated from the stem of Oplopanax elatus. The structures of compounds 1 and 2 were determined to be 9,10-epoxyheptadeca-4,6-diyne-3,8-diol and 10-methoxyheptadeca-4,6-diyne-3,8,9-triol,