Metabolomics is a new approach based on the systematic study of the full complement of low-molecular weight compounds (e.g. sugars, lipids, hormones, vitamins, secondary metabolites), both endogenous and exogenous, found within a cell, tissue, biofluid or organism. In order to avoid false expectation by using a metabolomics approach, it is important to have: (i) a properly planned design of the study based on a clear question to be answered, (ii) an appropriate knowledge of the equipments available; (iii) a proper statistical analysis and support and (iv) a validation of the results obtained. In the present short-review, these topics will be briefly described.