The primary objective of toxicology studies in the drug discovery process is to evaluate the safety of potential drug candidates. This is accomplished using relevant animal models and validated procedures. The ultimate goal is to translate the animal responses into an understanding of the risk for human subjects. To this end the toxicologist must be aware of the international guidelines for safety evaluation as well as traditional and nontraditional toxicology models. As described in this unit, the typical toxicology profile consists of safety pharmacology, genetic toxicology, acute and subchronic toxicology, absorption, distribution, metabolism, and excretion (ADME) studies, reproductive and developmental toxicity, and an evaluation of carcinogenic potential.