Medline PlusWelcome to MedlinePlus, a goldmine of good health information from the world's largest medical library, the National Library of Medicine. Health professionals and consumers alike can depend on it for information that is authoritative and up-to-date. MedlinePlus has extensive information from the National Institutes of Health and other trusted sources on over 900 diseases and conditions. There are directories, a medical encyclopedia and a medical dictionary, easy-to-understand tutorials on common conditions, tests, and treatments, health information in Spanish, extensive information on prescription and nonprescription drugs, health information from the media, and links to thousands of clinical trials.