Water extracts, ethanol extracts, and juice of Cusuta japonica, C, australis, and C. chinensis were prepared, and their cytotoxicity, antioxidant activity and inhibitory effects on tyrosinase activitiy and melanin biosynthesis were estimated by using melanoma Clone M-3. From this study; the following conclusions were attained. Extracts of Cuscuta japonica, C. australis, and C. chinensis showed noticeable cytotoxicity except ethanol extracts from the stem of C. australis. A maximual cytotoxicity was observed with tile ethanol extract from the seed of C, australis (87.39%). While the ethanol extract from the seed of C. japonica (91.88%) showed the most pronounced inhibitory effect on melanin biosynthesis, the water extract from the stem of C. japonica (1.05%) possessed very little inhibitory effect. The most inhibitory effect on tyrosinase activity was observed with the water extract from the stem of C. australis (76.67%). Howeverr the water extract from the stem of C. japonica showed a very poor effect on the inhibition of tyrosinase activity All the preparations, except extracts from the seed of C. australis were able to remove reactive oxygen species (ROS) in a dose-dependent manner. The juice of C. japonica demonstrated the strongest activity (59.02%).