Medline PlusYou can use MedlinePlus to learn about the latest treatments, look up information on a drug or supplement, find out the meanings of words, or view medical videos or illustrations. You can also get links to the latest medical research on your topic or find out about clinical trials on a disease or condition. There are directories, a medical encyclopedia, health information in Spanish, extensive information on prescription and nonprescription drugs, and links to thousands of clinical trials.