Epimedium koreanum Nakai is a wild medicinal plant commonly consumed in South Korea due to its beneficial health effects. In this study, the antimutagenic and immunological activities of E. koreanum Nakai extracts were investigated for their use in food. In the immunomodulating activity, the effects of E. koreanum Nakai on the B cell (Rhamos) and T cell (Molt-4) were investigated. The results showed that the growth and viability of the B and T cells were increased and activated more in the ethylacetate (1.35 and 1.48 times) and water fraction (1.30 and 1.40 times), respectively. In the Ames test, none of the fractions produced a mutagenic effect on Salmonella. typhimurium TA98 and TA 100. The ethylacetate fraction showed a strong antimutagenic effect (98%) on and a high butanol fraction (84%) of B(α)P in S. typhimurium TA98 and TA100, respectively. In 4-nitroquinoline-1-oxide (4NQO), all the solvent fractions showed an over 70% antimutagenic effect, except for the chloroform extract. Especially, ethylacetate and butanol showed strong inhibition of the mutagenic effects (80 and 90%) on 4NQO in S. typhimurium TA98 and TA100, respectively. These results provide preliminary data for the development of E. koreanum Nakai as an edible food material.