To analyse genetic relationships and intraspecific variation within Eleutherococcus senticosus, the polymerase chain reaction (PCR) was performed on total genomic DNAs of 10 Eleutherococcus collections. Ten primers were used for amplification, yielding 106 bands, of which 87 were polymorphic. The genetic diversity and genetic distance among 10 collections of Eleutherococcus species were used to describe the dendrogram showing the phylogenic relationship. The 10 collections were classified into two groups (groups I and II) at a similarity coefficient of 0.50. Group I included E. senticosus from Bukhaedo (Japan), E. sessliliflorus from Youngwal (Korea), E. seoulense and E. chiisanesis, while group II included several internal and Russian collections. The range of polymorphism was from 66.7 to 90.9% in the 87 amplified polymorphic DNA fragments. The similarity value of all collections ranged from 0.41 to 0.92, and the average genetic distance was 0.61. Thus, RAPD analysis was useful in determining genetic relatedness among collections and in identifying different genotypes of E. senticosus and other Eleutherococcus species. Also, the biological activity on DPPH radical scavenging, antilipid peroxidation in rat liver microsomes and cytotoxic sulforhodamine B (SRB) assay was evaluated using root extracts of E. senticosus, Odaesan, Korea. Ethyl acetate and n-butanol fractionation revealed strong antioxidant against scavenging on DPPH free radical and also ethyl acetate fractionation exhibited high antilipid peroxidative activities. In the cytotoxic effects were evaluated on seven human cancer cell lines, the values of 50% growth inhibition (GI(50)) were mostly below 30 microg/ml for crude extracts to be considered as significantly active.