Five abietane diterpenes were isolated from a hexane extract obtained from the roots of Aegiphila lhotzkyana and identified as uncinatone, cyrtophyllone B, teunvicenone E, sugiol and 12,16-epoxy-11,14-dihydroxy-6-methoxy-17(15 - 16)- abeo-abieta-5,8, 11,13,15-pentaene-3,7-dione. The last compound has only been described for this species. These compounds were tested for their antiproliferative effects on tumor cell lines using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl- 2H-tetrazolium bromide (MTT) assay and on sea urchin egg development, as well as for their lytic properties on mouse erythrocytes. All diterpenes reduced the viability of tumor cells and inhibited sea urchin egg cleavage. None of the tested compounds presented hemolytic activity.