The diethyl ether extract of Isodon excisus var. coreanus exhibited significant inhibitory activity in aromatase assay. Bioactivity-guided fractionation of the extract led to the isolation of three active compounds: inflexin (ent-1alpha-hydroxy-3beta,6a-diacetoxykaur-16-en-11,15-dione ) (1), ursolic acid (2), and ursolic acid 3-O-acetate (3).