A butanol extract of the soapberry plant, Phytolacca dodecandra (endod), is toxic at about 1 part per million to second and third instar Aedes, Culex, and Anopheles mosquitoes. Ova and pupae are not affected and adults die only after ingestion of concentrated endod. Endod extract is considerably more toxic than rotenone and about 100 times as active as a commercial saponin preparation. It is about twice as toxic as DDT when applied against DDT-resistant larval A. aegypti; 20 times less toxic for DDT-susceptible C. pipiens, and 40 times less toxic for DDT-susceptible A. quadrimaculatus. The concentration of endod required to kill mosquitoes is less than that which kills snails and fish.