Abstract: Artemisinine is a new antimalarial drug which has marked theraputic effect on patients suffering from chloroquine-resistant strain of Plasmodium falciparum. In order to find more potent antimalarials, we prepared ethers, carboxylic esters and carbonates of dihydroartemisinine. Forty seven new compounds were evaluated against chloroquineresistant strain of Plasmodium berghei in mice. Most of them are superior to artemisinine itself.The relationship between chemical structure and antimalarial activity in these derivatives of artemisinine is briefly mentioned.Some compounds tested against Schistosoma japonicum in laboratory animals are also shown to be more active than artemisinine.