Chemical constituents of Swertia patens. The whole plant of air-dried Swertia patens was extracted with 90% EtOH. The water extract was suspended in H₂O and extracted with petroleum ether, EtOAc and n-BuOH, successively. The compounds were isola- ted and purified by column chromatography from the EtOAc fraction, and identified based on spectral analyses (MS, ¹H-NMR, ¹³C- NMR). Eighteen compounds were isolated and elucidated as 3, 4-dihydro-1H,6H,8H-naptho [1,2-c:4,5-c', d'dipyrano-1, 8-dione (1), angelone (2), gentiogenal (3), erythricin (4), erythrocentaurin (5), gentianine (6), swertiakoside B (7), swertiamarin (8), 2'-O-actylswertiamarin (9), amarogentin (10), 1, 3, 5-trihydroxyxanthone (11), 1, 3-dihydroxy-5-methoxyxanthone (12), 1-hydroxy- 2, 3, 5-trimethoxyxanthone (13), gentiocrucine (14), 3-hydroxyphenylketone (15), n-hexacosyl ester 4-hydroxy-trans-cinnamate (16), n-hexacosyl ester 4-hydroxy-cis-cinnamate (17), and cholest-4-en-3-one (18). Compounds 1-7, 9-18 were obtained from S. patens for the first time.