With a view to investigating how Epimedium koreanum Nakai affects formation of melanin content in skin, we have measured change in the number of cell, melanin content, and tyrosinase activity by treating its aqueous extracts at various concentrations with B16 melanoma cells, the result of which is as follows: Firstly, cell viability has been shown as over 95% when treating with the aqueous extract of Epimedium koreanum Nakai up to 200 ug/mL, from which the effect of cell toxicology has not nearly appeared. Secondly, the number of cell has been slightly decreased than that of the control group when treating with the aqueous extract of Epimedium koreanum Nakai, which has not shown a statistical noteworthiness. Thirdly, the aqueous extract of Epimedium koreanum Nakai has increased in tyrosinase activity. Fourthly, the aqueous extract of Epimedium koreanum Nakai has promoted the formation of melanin content, its final product. According to the result, it is confirmed that Epimedium koreanum Nakai has the influence on promoting melanization of B16 melanoma cell, and it is considered that Epimedium koreanum Nakai can be applicable for curing vitiligo caused by decrease or loss of pigment through a systematic study.