Objective: To study the chemical constituents of the volatile oil from the aerial parts of Euphorbia wallichii. Method : The volatile oil was extracted by steam distillation and was identified by GC-MS. The relative amount of each constituent was calculated by peak area normalization method. Result: Twenty-five components were isolated

20 compounds were identified from the aerial parts of E. wallichii and their amount accounted 94.28% of total volatile oil. Conclusion: Chemical constituents of the volatile oils from the aerial parts of E. wallichii include organic acids

alkane

terpenoids and its derivatives. The main constituents were hexadecanoic acid (60.36%)

nor-prist-2-one (7.674%) and tetradecanoic acid (5.433%).