The components of the essential oil from Caesalpinia decapetala (Roth) Alston (jaketsuibara) were analyzed by gas chromatographyâmass spectrometry (GCâMS). Seventy-two components, representing 99.6% of the total oil were identified by GCâMS. The main components of the oil were β-caryophyllene (17.2%), followed by β-myrcene (16.6%), (E)-β-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 β-myrcene and β-caryophyllene affect spicy-odor of the oil, while, (Z)-β-ocimene and (E)-β-ocimene contributed to the sweet odor through gas choromatography olfactometry (GCâO) 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.