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Search Tips

How do I search MedlinePlus?

The search box appears at the top of every MedlinePlus page.

To search MedlinePlus, type a word or phrase into the search box. Click the green “GO” button or press the Enter button on your keyboard. The results page shows your first 10 matches. If your search yields more than 10 results, click on Next or page number links on the bottom of the page to view more.

The default display for MedlinePlus searches is a comprehensive list of 'All Results'. Users can focus their search on one part of the site by navigating to an individual collection of results.

What do the links in the 'Refine by Type' box under 'All Results' mean?

Your initial search results show matches from all of the MedlinePlus content areas. The links in the 'Refine by Type' box under 'All Results' represent sets of MedlinePlus content areas, known as collections. The collections help you narrow your search by displaying results exclusively from one collection.

MedlinePlus has the following collections:

  • Health Topics: More than 1,000 pages covering wellness issues and the symptoms, causes, treatment, and prevention of diseases, illnesses, and health conditions.
  • Medical Encyclopedia: Articles and images related to hundreds of diseases and conditions.
  • External Health Links: Links to webpages from selected government agencies and health-related organizations. These links may include interactive tutorials, videos, easy-to-read materials, and National Institutes of Health (NIH) publications. They appear on MedlinePlus Health Topic pages, but they're listed individually in search results.
  • Medical Tests: Descriptions of nearly 300 medical tests. Each description includes what the test is used for, why a healthcare provider might order the test, how the test will feel, and what the results may mean.
  • Drugs and Supplements: Prescription and over-the-counter medication information and information on herbs and supplements.
  • Genetics: Information on more than 1,300 genetic conditions, 1,400 genes, each of the 23 pairs of human chromosomes, and mitochondrial DNA (mtDNA). MedlinePlus Genetics also includes an educational handbook called Help Me Understand Genetics, which explores topics in human genetics from the basics of DNA to genomic research and personalized medicine.
  • National Institutes of Health: Links to articles and images created by the 27 Institutes and Centers at NIH. Each Institute or Center has a specific research agenda, often focusing on particular diseases or body systems.
  • MedlinePlus Magazine: Articles that appear in the online version of the NIH MedlinePlus Magazine.
  • Healthy Recipes: Recipes that show you how to prepare tasty, healthy meals. The recipes use easy-to-follow instructions and include nutrition information.
  • Multiple Languages: Links to high-quality health information in languages in addition to English and Spanish.

Can I search for a phrase?

Yes, you can search for a phrase by enclosing words in quotation marks. For example, "health services research" retrieves pages containing that phrase.

Will the search automatically expand my search words to include synonyms?

Yes, a built-in thesaurus automatically expands your search. The thesaurus contains a list of synonyms from NLM's MeSH® (Medical Subject Headings) and other sources. When there is a match between a search term and a word in the thesaurus, the thesaurus automatically adds the synonym(s) to your search. For example, if you search for the word swelling, results are automatically retrieved for edema.

Is Boolean searching allowed? What about wildcards?

Yes, you can use the following operators: OR, NOT, -, +, *

You do not need to use AND because the search engine automatically finds resources containing all of your search terms.

OR Use when you want either term, but not necessarily both, to appear in the results
Example: Tylenol OR Acetaminophen
NOT or - Use when you do not want a particular term to appear in the results
Examples: flu NOT bird or flu -bird
+ Use when you require the exact word to appear in all of the results.
For multiple words, you must use + in front of each word that must be exact.
Example: +tylenol finds results with the brand name "Tylenol", without automatically including all results with the generic synonym "acetaminophen".
* Use as a wildcard when you want the search engine to fill in the blank for you; you must enter at least three letters
Example: mammo* finds mammogram, mammography, etc.

Can I restrict my search to a specific website?

Yes, you can restrict your search to a specific site by adding 'site:' and the domain or URL to your search words. For example, if you want to find breast cancer information in MedlinePlus only from the National Cancer Institute, search on breast cancer

Is the search case sensitive?

The search engine is not case sensitive. The search engine matches words and concepts regardless of capitalization. For example, a search on alzheimer's disease also retrieves pages containing the words Alzheimer's Disease.

What about searching for special characters like ñ?

You can use special characters in your search, but they're not required. When you use diacritics in your search, the search engine retrieves pages that contain those diacritics. The search engine also retrieves pages that contain the term without special characters. For example, if you search on the word niño, your results include pages that contain the word niño or nino.

Will the search check my spelling?

Yes, the search engine suggests replacements when it doesn't recognize your search term.

Why didn't my search find anything? What should I do?

Your search didn't find anything because you spelled a word incorrectly or because the information you're looking for isn't available in MedlinePlus.

If you spelled a word wrong, the search engine consults the thesaurus for a possible match and makes suggestions. If the search engine doesn't give you suggestions, consult a dictionary for the correct spelling.

If the information you're looking for isn't available on MedlinePlus, you can try searching other resources from the National Library of Medicine. For example, you can search MEDLINE/PubMed, NLM's database of biomedical journal literature.