Toxicogenomics is related to pharmacogenomics, combining toxicology, genetics, molecular biology, and environmental health to elucidate the response of living organisms to stressful environments or toxic agents. Likewise, new drug candidates can be screened through a combination of gene expression profiling and toxicol-ogy to understand gene response and possibly predict safety (Furness, 2002). Genomic techniques utilized include gene expression level profiling and single-nucleotide polymorphism analysis of the genetic variation of individuals generally employing micro-array technology. Toxicogenomic studies are corre-lated to adverse toxicological effects in clinical trials so that suitable biomarkers for these adverse effects can be developed. Using such methods, it would then theoretically possible to test an individual patient forhis or her susceptibility to these adverse effects before administering a drug. Patients that would show the marker for an adverse effect would be switched to a different drug. At this time however, the field is in its infancy.