Abstract:Two new diterpenoid quinones (dimer), xanthanthusin B (la) and xanthanthusin C (2a) and, taraxerol and oleanolic acid, were isolated from Coleus xanthanthus C. Y. Wu et Y. C. Huang by column chromatography on silica geL The structure of xanthanthusin B (la) and xanthanthusin C (2a) were elucidated respectively as (13S, 15S)-2a, 12a-diacetoxy-13-spiro-cyclopropyl-grandidon A (la) and 7-epi-xanthanthusin B (2a) by spectroscopic methods.