In the post-genomic era, several profiling tools have been developed to provide a more comprehensive picture of tumour development and progression. The global analysis of metabolites, such as by mass spectrometry and high-resolution ¹H nuclear magnetic resonance spectroscopy, can be used to define the metabolic phenotype of cells, tissues or organisms. These 'metabolomic' approaches are providing important information about tumorigenesis, revealing new therapeutic targets and will be an important component of automated diagnosis.