Metabonomics is a branch of ‘‘omics’’ technologies focused on the analysis and measurement of endogenous metabolites. The workhorse of metabonomic applications has been nuclear magnetic resonance (NMR) spectroscopy, but applications and approaches incorporating separation techniques such as high performance liquid chromatography (HPLC), gas chromatography (GC), and mass spectrometry (MS) are being used with increasing frequency. Metabonomic approaches have been applied broadly in botanical sciences and biomedical studies, including both diagnostic medicine and basic research. To date, some of the most signiﬁcant efforts and advances in metabonomics have been made relative to plant science (for reviews see Refs. 1 and 2; Feihn et al. 2000). This review will focus on the technological aspects of metabonomic platforms, data collection and analysis, and will emphasize the use of metabonomics in understanding the pathophysiological changes associated with toxicological responses.