Systems Toxicology is defined as the study of the perturbation of biological systems by chemicals and stressors, monitoring changes in molecular expression and conventional toxicological parameters, and iteratively integrating response data to describe the functioning organism. Systems toxicology provides an integrated and iterative assessment of the toxicity of agents based on the analysis of -omics (genomic, proteomic and metabolomic, etc.) data together with classic toxicology endpoints. One aspect of this approach is to develop and apply metabolomic, proteomic, genomic and other data-rich analyses to construct an integrated network of molecular changes as a function of exposure to a toxic insult.