To evaluate the ability of inhibiting tyrosinase enzyme, a catalyst for melanin production causing skin pigmentation disorder of the extract of Vernonia cinerea (L.) Less., Artemisia vulgaris and Eclipta alba L. Materials and Methods: Enzyme tyrosinase and the plants of  Vernonia cinerea (L.) Less., Artemisia vulgaris and  Eclipta alba L. Results: Enzyme tyrosinase transformed L-tyrosinse into dopachrome at the optimum concentration of  350 U/ mL. The pH of reaction was about 6.8 – 7, at the proper temperature of 37ºC after 15 minutes of incubation. Quantitative result of polyphenol content showed that V.cinerea (L.) Less. contained the highest content of polyphenol (71,73±0,05 mg GAE/g DW) and their content in E. alba (L.) Hassk was the lowest (46,62±0,21 mg GAE/g DW). The ethanolic extract of all the plants inhibited enzyme tyrosinase activity. However, among investigating medicinal plants, V. cinerea (L.) Less. showed the strongest bioactivity.