An online health information resource for patients and their families and friends. It is a service of the National Library of Medicine (NLM), the world's largest medical library, and a part of the National Institutes of Health (NIH). Offers information on health topics, human genetics, medical tests, medications, dietary supplements, and healthy recipes. Sourced from about 500 selected organizations. Offers almost 22,000 links to authoritative health information in English and more than 13,000 links to information in Spanish.