OBJECTIVE To study the chemical constituents of Swertia mileensis. METHODS The air-dried whole plants of S. mileensis were extracted with 50% EtOH. The EtOH extract was suspended in H20 and extracted with petroleum ether, CHCl3 and n-BuOH successively. The compounds were isolated and purified by column chromatography from the CHCl3 fraction, and identified based on spectral analyses (MS, H-NMR, 13C-NMR). RESULTS Twelve compounds were isolated from S. mileensis, and were elucidated as 1,5, 8-trihydroxy-3-methoxyxanthone (1), 1-hydroxyl-2, 3, 5, 7-tetramethoxyxanthone (2), 1-hydroxyl-3, 5, 8-trimethoxyxanthone (3), 1-hydroxyl-2, 3, 4, 6-tetramethoxyxanthone (4), 1-hydroxyl-2, 3, 4, 7-tetramethoxyxanthone (5), 1,8-dihydroxy-3, 5-dimethoxyxanthone (6), 1, 7-dihydroxy-3, 8-dimethoxyxanthone (7), 1, 3, 5, 8-tetrahydroxyxanthone (8), balanophonin (9), oleanolic acid (10), maslinic acid (11), sumaresinolic acid (12). CONCLUSIONS Compounds 1, 3, 7-9, 11 and 12 were obtained from S. mileensis for the first time.