Two sesquiterpene endoperoxides, 1S, 4R, 6R-1, 4-endoperoxy-bisabola-2, 10-diene (I), 1R, 4S, 6R-1, 4-endoperoxy-bisabola-2, 10-diene (II), and a sesquiterpene hydroperoxide, 1beta-hydroperoxygermacra-4 (15), 5, 10 (14)-triene (III) were isolated from the aerial parts of Artemisia stolonifera (Compositae). Their chemical structures were assigned by spectral evidences. Compounds I and II exhibited cytotoxicity against five human tumor cell lines with their ED50 values ranging from 0.20 to 5.43 microg/ml and from <0.1 to 0.87 microg/ml, respectively.