Two abietane diterpenes were isolated from a hexane extract of Hyptis martiusii roots and identified as carnasol 11,14-dihidroxy-8,11,13-abietatrien-7-one. These compounds were tested for their antiproliferative effects on tumor cell lines using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide and on the sea urchin egg development. Both compounds displayed cytotoxic activity against tumor cell lines, but only carnasol was able to inhibit the sea urchin egg cleavages.