MEDLINEplus

MEDLINEplus is a service of the National Institutes of Health and the National Library of Medicine to provide health information resources for America's health care consumer and practitioner. MEDLINEplus is for anyone with a medical question. Both health professionals and consumers can depend on it for accurate, current, medical information. This service provides access to extensive information about specific diseases and conditions and also has links to consumer health information from the National Institutes of Health, dictionaries, lists of hospitals and physicians, health information in Spanish and other languages, and clinical trials.
http://www.nlm.nih.gov/medlineplus