A new oleanane-triterpene, 3${eta}$-acetoxy-11${alpha}$-benzoyloxy-13${eta}$-hydroxyolean-1 2-one (1), was isolated along with a known quinone-methide triterpene, pristimerin (2), from the root bark of Siphonodon celastrinneus Griff., a Thai medicinal plant of the family Celastraceae. Their structures were determined based on spectroscopic analysis.