Swertia is a genus in the gentian family containing plants sometimes referred to as the felworts. Some species bear very showy purple and blue flowers. Plants of genus Frasera are sometimes considered part of this genus, sometimes as a separate genus, and sometimes as synonymous. Swertia contains main chemicals sawertiamarine, mangeferin and amarogenitine 1,5, 8-trihydroxy-3-methoxyxanthone, 1-hydroxyl-2, 3, 5, 7-tetramethoxyxanthone, 1-hydroxyl-3, 5, 8-trimethoxyxanthone, 1-hydroxyl-2, 3, 4, 6-tetramethoxyxanthone, 1-hydroxyl-2, 3, 4, 7-tetramethoxyxanthone, 1,8-dihydroxy-3, 5-dimethoxyxanthone, 1, 7-dihydroxy-3, 8-dimethoxyxanthone, 1, 3, 5, 8-tetrahydroxyxanthone , balanophonin, oleanolic acid, maslinic acid, and sumaresinolic acid. Swerilactones from Swertia mileensis showed anti-hepatitis B virus activity in vitro.