Nonclinical safety evaluation plays a critical role in the process of new drug development.International Conference on Harmonization (ICH) guideline M3 (R2) provides a key direction for the nonclinical safety evaluation process.Proper strategies and toxicological studies should be considered together to move the drug candidates forward efficiently and quickly to support clinical plans and market registration.Updates on ICH guidelines,such as ICH S6 and ICH S9,have great impact on the direction of development.With the increasing cost of development and competition in the industry,elements like predictivity,animal models,and regulatory compliance are also very important in the process.Therefore,an insight into all these factors is essential to toxicologists in the safety evaluation process.The ability to use the overall knowledge will result in a quicker and better new drug development program.