OBJECTIVE: To analyze the essential oils from flowers, leaves, stems, roots, and fruits of Chaihu(Radix Bupleuri Chinensis).METHODS: We extracted essential oils from different parts of Chaihu(Radix Bupleuri Chinensis) using a steam distillation method. The essential oils were analyzed by gas chromatography-mass spectrometry(GC-MS). Data were collected in full scan mode(m/z 60-600). Volatile components were identified based on their retention indices and by comparing their mass spectra with those in the National Institute of Standards and Technology 2005 database assisted by tandem mass spectrometry information. The relative content of each constituent wasdetermined by area normalization.RESULTS: We identified 111 components, of which12 were common to all 5 parts, 30 were found only in roots, 14 were found only in flowers, 6 were found only in leaves, 4 were found only in stems,and 17 were found only in fruits.CONCLUSION: Our results show that the stems,flowers, leaves, and fruits of Chaihu(Radix Bupleuri Chinensis)contain a high concentration of essential oils, and that the exact composition of the essential oils differs among the plant parts. To develop new medicines and make full use of the Chaihu(Radix Bupleuri Chinensis)resource, it is important to characterize the essential oils from different parts of the plant. In future research, it will be important to determine the pharmacological effects of the various components and the essential oil mixtures. OBJECTIVE: To analyze the essential oils from flowers, leaves, stems, roots, and fruits of Chaihu (Radix Bupleuri Chinensis). METHODS: We extracted essential oils from different parts of Chaihu (Radix Bupleuri Chinensis) using a steam distillation method. The essential The oils were analyzed by gas chromatography-mass spectrometry (GC-MS). Data were collected in full scan mode (m / z 60-600). Volatile components were identified based on their retention indices and by comparing their mass spectra with those in the the National Institute of Standards and Technology 2005 database assisted by tandem mass spectrometry information. The relative content of each constituent was determined by area normalization. RESULTS: We identified 111 components, of which 12 were common to all 5 parts, 30 were found only in roots, 14 were found only in flowers, 6 were found only in leaves, 4 were found only in stems, and 17 were found only in fruits.CONCLUSION: Our results show that the stems, flowers, leaves, and fruits of Ch aihu (Radix Bupleuri Chinensis) contains a high concentration of essential oils, and that the exact composition of the essential oils diverse among the plant parts. To develop new medicines and make full use of the Chaihu (Radix Bupleuri Chinensis) resource, it is important to characterize the essential oils from different parts of the plant. In future research, it will be important to determine the pharmacological effects of the various components and the essential oil mixtures.