Objective: To study the chemical constituents of volatile oil extracted from roots and stems of Bupleurum chinense cultivated in Gansu Province. Method: The volatile oil was extracted from different parts (roots and stems) of Bupleurum chinense with steam distillation method

and the chemical constituents were analyzed and identified by gas chromatography-mass spectrometry (GC-MS). The relative content of each constituent was calculated by area normalization method. Result: The yield of extracted volatile oil from roots and stems of B. chinense was 0.04% and 0.01%

respectively. A total of 95 compounds were identified from the two parts

of which 52 from roots and 72 from stems. There were 29 common compounds in both parts and accounted for 61.29% and 53.54% of the total volatile oil

respectively. The major components of volatile oil from roots include hexanal (17.00%)

2-pentyl-furan (8.10%)

palmitic acid (6.71%)

5-(1-methylethyl)-2-methyl-phenol (6.65%)

thymol (5.23%)

heptanal (4.64%)

and etc. The major components of volatile oil from stems include n-hexadecanoic acid (10.79%)

3-methyl-4-isopropylphenol (8.31%)

carvacrol (6.19%)

hexanal (6.09%)

2-pentyl-furan (4.42%) and etc. Conclusion: There are big differences both in the kind and content of volatile oil from different parts of B. chinense cultivated in Gansu Province. The results can be taken as a basis for the further development and utilization of B. chinense.