Five new amino acid-sesquiterpene adducts, saussureamines A, B, C, D, and E, were isolated from Chinese Saussureae Radix, the dried root of Saussurea lappa CLARKE, together with a new lignan glycoside, (-)-massoniresinol 4"-O-β-D-glucopyranoside. Their structures were determined on the basis of chemical and physicochemical evidence. Among of these compounds. saussureamines A, B, C showed anti-ulcer effect on HCl / ethanol-induced lesions in rats, and saussureamine A also exhibited a inhibitory activiity on stress-induced ulcer formation in mice. During the course of these studies, facile conversion from sesquiterpene having an α-methylene γ-lactone function to amino acid-sesquiterpene adduct has been accomplished by means of Michael type addition reaction.