1 2 -4 2: R 1 = β−OH, R 2 = H 3: R = α−OH, R 2 = H 4: R 1 = α−OH, R 2 = OH O O OH O 11 13 5Four sesquiterpene lactones with the germacrane structure were isolated from the aerial part of Stizolophus balsamita. X-ray structure analyses showed that two of them were previously known balsamin derivatives. A third was a crystalline isomorphous mixture of the known lactone stizolin and 11,13-dihydrostizolin in a 53:47 ratio. The biological activities of the balsamin derivatives were investigated.