To isolate biologically active compounds which exhibit tyrosinase inhibition activity and ultimately express skin whitening effect, 14 oriental herbal drugs were screened in ter ms of tyrosinase inhibition. For this purpose, in vitro enzyme assay system for tyrosinase, so called Pomerantz method with some modifications has been established. Crude methanolic extracts from 14 herbal drugs were made and examined for their inhibitory activity against tyrosinase. Those extracts from Cnidii Rhizoma, Arecae Semen, Caryophylli Flos, and Ephedrae Herba showed strong inhibitory activities on mushroom tyrosinase. Therefore, crude methanolic extracts from those 4 herbal drugs were further fractionated using ether, butanol and water. respectively. The ether and n-butanol extracts from Arecae Semen and the n-butanol and water extracts from Caryophylli Flos, respectively, showed relatively strong tyrosinase inhibitory activity compared to arbutin.