sure that drugs marketed in this country are safe and effective. CDER does not test drugs, although the Center's Office of Testing and Research does conduct limited research in the areas of drug quality, safety, and effectiveness.CDER is the largest of FDA's five centers. It has responsibility for both prescription and nonprescription or over-the-counter (OTC) drugs. For more information on CDER activities, including performance of drug reviews, post-marketing risk assessment, and other highlights, please see the CDER Update: Improving Public Health Through Human Drugs1 The other four FDA centers have responsibility for medical and radiological devices, food, and cosmetics, biologics, and veterinary drugs. Some companies submit a new drug application (NDA) to introduce a new drug product into the U.S. Market. It is the responsibility of the company seeking to market a drug to test it and submit evidence that it is safe and effective. A team of CDER physicians, statisticians, chemists, pharmacologists, and other scientists reviews the sponsor's NDA containing the data and proposed labeling2.