DrugMatrix is a comprehensive rat toxicogenomics database and analysis tool developed to facilitate the integration of toxicogenomics into hazard assessment. Using the whole genome and a diverse set of compounds allows a comprehensive view of most pharmacological and toxicological questions and is applicable to other situations such as disease and development. Overall design: Complete Drug Matrix dataset for primary rat hepatocytes. Cells were exposed to toxicants in culture medium and harvested after 0.67 or 1 day.