OBJECTIVE The metabonomics utilizing LC-ESI-MS and multivariate statistical technique have been applied to investigate the metabolic profiles of hypoxic preconditioning of mice by the model of acute repetitive hypoxia.METHODS The brain and heart metabolomie profiles of hypoxic preconditioning in mice were compared with those of the control mice.Whole brain and heart tissues were collected for study from both normal mice and those suffered acute repetitive hypoxia.The samples were analyzed by LC-ESI-MS detection and the pattern recognition using partial least squares discriminate analysis (PLS-DA).Candidate molecules were screened and compared from the Human Metabolome Database (HMDB) and METLIN databases.The retention time and corresponding tandem mass results were employed to identify the potential biomarkers.RESULTS The results showed that the levels of phenylalanine, valine, proline and glutamine were all increased both in brain and heart in the hypoxia group, while creatine was decreased.In addition, γ-aminobutyric acid was decreased in brain of hypoxia group.