A complex prescription (CP) used traditionally for the treatment of vitiligo was prepared from water extract of eight plant materials. To study the mechanism of this preparation its effect on gene expression of B-16 murine melanoma cells was estimated using differential display method (DDRT-PCR). The results showed that the complex prescription was effective in activating the mitochondrial ATP synthase-6 (ATPase-6) gene expression in B-16 murine melanoma cells. This activity may play an important role in its treatment of vitiligo.