Objective: To analyze the chemical constituents of volatile oil from the xylem and bark of Acronychia pedunculata in Hainan and its antibacterial activity and cytotoxicity. Method: The volatile oil was extracted by water-steam distillation and analyzed by GC-MS. The relative contents of the compounds were determined by normalization. The compounds were characterized by NIST05 and WILEY275L database matching. Antibacterial activities of the xylem and bark oil were assayed by the filter paper disc agar diffusion and the cytotoxicity of them was evaluated by MTT. Conclusion: 77 compounds were identified from the xylem oil which constituting 67.74% of the total oil and its main constituents were palmitic acid(18.84%)

α-copaene (7.94%)

δ-cadinene (3.71%)

(E

Z)-2

4-decadienal (3.45%) and alloaromadendrene (3.30%). 75 compounds were identified from the bark oil which constituting 96.25% of the total oil and its main constituents were α-pinene (46.70%)

α-copaene (19.81%)

δ-cadinene (5.80%)

alloaromadendrene (4.46%)

and limonene (3.53%). 39 compounds were identified both from the xylem oil and bark oil. The volatile oil from the bark showed antibacterial activity against Staphylococcus aureus

but the oil from xylem was inactive. The oil from xylem and bark showed significant cytotoxicactivities towards chronic myelogenous leukemia (K562)

human hepatoma(SEL-7402) and human gastric carcinoma (SGC-7901).The activity of the former was better than the latter.