Two new sesquiterpenes, named tussilagonone (1) and neotussilagolactone (2), together with two known sesquiterpenes (3) and (4) and two phthalic acid derivatives (5) and (6), were isolated from the flower buds of Tussilago farfara . The structures of (1) and (2) were determined on the basis of spectroscopic analyses. Compounds (1) and (2) exhibited activities against platelet aggregation caused by platelet activating factor.
