The transportation, care, and use of animals should be in accordance with the Animal Welfare Act and other applicable Federal laws, guidelines, and policies. The animals selected for a procedure should be of an appropriate species and quality and the minimum number required to obtain valid results. Methods such as mathematical models, computer simulation, and in vitro biological systems should be considered. Proper use of animals, including the avoidance or minimization of discomfort, distress, and pain when consistent with sound scientific practices, is imperative. Unless the contrary is established, investigators should consider that procedures that cause pain or distress in human beings may cause pain or distress in other animals. Institutional Animal Care and Use Committee (IACUC) is comparable with the Institutional Ethical Committee (IEC), reviewing research proposals involving the use of laboratory animals. A detailed discussion on the purpose of use of animals in scientific/medical research has been provided in this chapter.