The wild sarsaparilla (Aralia nudicaulis) plant is richly distributed in North America, mainly in Canada. In the present study, 24 extracts were obtained from the rhizome, stem, leaf and fruit of wild sarsaparilla. In the presence of RH (hexane fraction from the rhizome), the survival rate of WiDr (human colon cancer cell) was 3.5 +/- 2.7% (IC50 = 30.1 +/- 3.5 microg/ml) and that of Molt (human leukemia cell) was 2.4 +/- 2.8% (IC50 = 7.0 +/- 0.6 microg/ml). The survival rate of HELA (human cervix cancer cell) was only 1.8 +/- 0.9% in the presence of FH (hexane fraction from the fruit of wild sarsaparilla) (IC50 = 33.3 +/- 2.7 microg/ml). The cytotoxicities of RH and FH against normal human umbilical vein endothelial cells were significantly lower than against the tested human cancer cells. RH appeared to be the best extract against WiDr and Molt, whereas FH was the most effective against HELA. Because of the rich natural supply, simple extraction procedure and high yield, RH and FH of wild sarsaparilla have the potential to be developed into selective anticancer nutraceutical and/or pharmaceutical products with few side-effects and low cost.