Centers for Disease Control and Prevention - This site contains valuable publications, such as CDC prevention guidelines and Morbidity and Mortality Weekly Report (MMWR).

Food and Drug Administration - The FDAs web site contains a wealth of useful information for consumers, healthcare practitioners, and medical writers.

Center for Drug Evaluation and Research (CDER), a branch of the FDA, reviews new drug development applications and approves post-drug activities; their web site lists recently approved drugs and their indications.