The Plant Extract Bank was established by 21 Century Frontier R&D Program. It has began selling a research plant extract samples to support many Korean scientists since 2001. The plant extracts were tested for insecticidal activities. A total of 19,100 ethanolic and methanolic extracts of differentplant species from 23 nations including Costa Rica, Philippines, India and South Africa were evaluated for their larvicidal activities against Aedes aegypti, the major vector of dangue, dangue hemorhagic fever and yellow fever. The larval mortalities were observed 24h after treating the larvae to the extracts. At 500 ppm, 754 extracts showed >80% larval mortality in the 24h exposure. Among the extracts tested, the highest larval mortality was observed in the methanol extracts of Piper guianense, P. nigrum, P. mocropodum, P. sem-immersum, P. magen and P. pubicatulm.