Objective: To investigate the chemical constituents in the supercritical carbon dioxide (CO2) extract of fruits of Piper nigrum (black pepper) in Hainan. Method: The black pepper oil was extracted by supercritical fluid extraction and its chemical constituents were separated

determined and identified by gas chromatography-mass spectrometry combined with computer retrieval in compound databases. The relative percentage content of each compound was calculated by peak area normalization method. Result: 32 compounds were separated from black pepper oil and 24 of them were identified

which covered 86.86% of the total oil. The major constituents with higher relative content were piperine (39.47%)

chrondriamide B (6.25%) and oleic acid (5.49%). Conclusion: Piperine is the major constituent in the black pepper oil. The research provided basis for the further research and exploitation of black pepper oil.