Ixeris chinensis (Thunb.) Nakai, Herbs 5-50 cm tall, perennial, rosulate, glabrous. Taproot, often with shoot-bearing lateral roots. Stems usually few to several, rarely solitary, ascending-erect to erect, branched from base or higher up. Rosette leaves oblanceolate, elliptic, narrowly elliptic, or ± linear, 6-24 × 1-2 cm, undivided or pinnatifid to pinnatipartite, basally attenuate, margin entire or sinuate-dentate, apex obtuse, acute, or attenuate Two new guaianolides, named chinensiolides D (5) and E (6), were isolated from Ixeris chinensis Nakai, and their structures were determined to be 10alpha-hydroxy-3-oxoguaia-11(13)-eno-12,6alpha-lactone (5) and 10alpha-hydroxy-3beta-O-[2,6-di(p-hydroxyphenylacetyl)-beta-glucopylanosyl]guaia-4(15),11(13)-dieno-12,6alpha-lactone (6). The first isolation of (11S)-10alpha-hydroxy-3-oxoguaia-4-eno-12,6alpha-lactone (4) from natural sources and its characterization are also reported.