Abstract: An unknown minor resin acid methyl esters mixture was first separated from main resin acid methyl esters by column ehromatography. Two unknown resin acids were identified by GC-MS, which are 8,15-isopimaradien-18-acid and 8,15-pimaradien-l8-acid. After further purification by preparative HPLC and recrystallization, another small amount of constituent was isolated, which was shown to be Elliotinoic acid by the identification of its m.p., ultraviolet and mass spectrum.