In the field of critical care medicine，the so-called ‘diseases’ are often ‘syndromes’. The same clinical outcome may have different etiologies. In fact，the current assessment of these syndromes does not reflect the whole changes of the patients’ body. Metabolomics is the latest ‘omics’ technique，which analyzes the small molecule metabolites of organisms or specific biological sam－ples comprehensively. And it provides an insight of actual（health or illness） condition of organisms from the cell status. Techniques for a variety of biological fluids，such as gas chromatography-mass spectrometry，liquid chromatograph-mass spectrometry have been used in ICU for the metabolic analysis. And they have been used in the diagnosis and prognosis of the syndromes or diseases，such as sepsis，acute respiratory distress syndrome，acute kidney injury and so on in the ICU. In this review，we will focus on the develop－ment of metabolomics analysis in critical care medicine.