We have tested tyrosinase inhibitory activity on the methanol extracts of 23 species marine algae and 23 species traditional medicinal plant. Among them, four medicinal plants, Ephedra sinica, Atractylodes japonica, Pinnelia ternata, and Citrus aurantium, showed strong inhibition potency over 90% at concentration of 0.33 mg/mL. Also, two marine algae, Enteromorpha compressa and Sargassum singgildianum showed mild inhibition potency over 50% at concentration of 0.33 mg/mL.