Flavonoids are class of polyphenolic compounds widely distributed in the plant kingdom, which display a variety of biological activities, including antiviral, antithrombotic, antiiflammatory, antihistaminic, antioxidant and free-radical scavenging abilities. To determined flavonoid, myricetin in the presence of other antioxidants - vitamin C and vitamin E - can exert antioxidative properties not only directly by modulating the AOE system but also scavenging free radical, we investigated cell viability, antioxidant enzyme activities and ROS level in B16F10 murine melanoma cell. B16F10 cells were exposed to medium containing myricetin in the presence or absence of vitamin C or vitamin E for a period of 24 hr. Cell viability was measured by MTT assay. In co-treating myricetin with other antioxidants, CAT activities were increased, compared with control, but SOD and GPx activities were decreased, compared with each antioxidant treated groups . In the group of myricetin or myricetin present with other antioxidants, ROS levels were decreased dose-dependently. Especially, myricetin present of other antioxidants were decreased compared with myricetin.