Abstract: Cryptomeria japonica is one of common coniferous trees in Taiwan forest. Extraction of natural compounds from secondary metabolites of sugi tree can expand the utilization of forest products. The target of this project is to isolate antioxidative compounds from the ethanolic extract of sugi bark. Constituents of the active subfractions are analyzed by chromatographic techniques and spectral analyses. Antioxidative activities of compounds are examined by antioxidant assays, including DPPH radical scavenging test, reducing power assay, and TEAC assay, etc. Effects of bark extract and active fraction on the inhibition of PGE2 and COX-2 production are also evaluated. Through this research, it is expected that extract from sugi bark is of great potential as antioxidative agent. This work would be helpful to expand the utilization of sugi bark and increase the economic values of sugi plantations.