the components of the essential oil from caesalpinia decapetala (roth) alston (jaketsuibara) were analyzed by gas chromatography-mass spectrometry (gc-ms). seventy-two components, representing 99.6% of the total oil were identified by gc-ms. the main components of the oil were -caryophyllene (17.2%), followed by -myrcene (16.6%), (e)--ocimene (12.4%), limonene (10.4%), and caryophyllene oxide (9.6%). monoterpenoids and sesquiterpenoids accounted for about 90% of the essential oil. with regard to odor components from essential oil of c. decapetala, it was revealed that -myrcene and -caryophyllene affect spicy-odor of the oil, while, (z)--ocimene and (e)--ocimene contributed to the sweet odor through gas choromatography olfactometry (gc-o) and aroma extraction dilution analysis (aeda). on the basis of flavor dilution (fd)-factors and odor activity values (oavs), monoterpenoids and sesquiterpenoids influence the aroma of this plant and participated in the characteristic odor of c. decapetala.