Abstract: OBJECTIVE To study the chemical components of the cytotoxic portion of the fresh rejuvenated fruits of Juglans mandshurica. METHODS The cytotoxicity of four elutes from macro-porous resin chromatography was estimated by MTT assay against human stomach BGC803 cancer cells. The 30% ethanol elute showing the strongest activities was isolated by silica gel chromatography and reverse phase silica gel chromatography. RESULTS 1,4,5-trihydroxynaphthalene-1,4- di-O-β-D-glucopyranoside(1), 1,4,5-trihydroxynaphthalene-1,5-di-O-β-D-glucopyranoside(2), 1,4,8-trihydroxynaphthalene-1-O-β-D-glucopyranoside(3), 1,4,8-trihydroxynaphthalene-1-O-β-D-6′-O-(3″,4″,5″-trihydroxybenzoyl) glucopyranoside(4) were isolated and their structures were determined by NMR spectrum. CONCLUSION There are naphthalenyl glucosides in the cytotoxic portion of fresh rejuvenated fruits of Juglans mandshurica and they may play a significant role in its antitumor activities.