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MedlinePlus Connect: Technical Information

MedlinePlus Connect is available as a Web application or a Web service.

Sign up for the MedlinePlus Connect email list to keep up with developments and exchange ideas with your colleagues. It's the best way for us to keep you informed of updates and enhancements. Please tell us if you implement MedlinePlus Connect by contacting us.

Technical Quick Facts:

  • MedlinePlus Connect is an API provided by the National Library of Medicine. It is available as a Web application or a Web service.
  • MedlinePlus Connect will update and maintain the responses to code requests. The possible types of queries and reponses are described on the How it Works page.
    • Queries are URL-based. Connect uses the GET method not POST.
    • Only one code can be submitted per request.
  • Supports the HL7 Context-Aware Knowledge Retrieval (Infobutton) standard.
  • Connects using HTTPS connections.
  • A personal health record (PHR) or electronic health record (EHR) vendor may activate MedlinePlus Connect at an enterprise level so it is available to all users.
  • Health IT managers, such as at hospital systems or health care providers, may implement MedlinePlus Connect in their system if they have the administrative rights to make these adjustments.

For detailed implementation instructions, request parameters, demonstrations, and examples, go to the

MedlinePlus Connect Implementation Options

Web Application

How does it work?

  • Responds to requests with an on-demand, formatted MedlinePlus Connect Web page
  • The page is responsively-designed, has a toggle button for Spanish/English (when appropriate).
  • Web Application demonstration

Technical Details and Demonstrations

Web Service

How does it work?

  • Responds to requests with XML, JSON, or JSONP, which implementers can use to incorporate MedlinePlus information and links into any health IT interface
  • It is a REST-based Web Service
  • The implementer may select which MedlinePlus links and information to provide from within the system instead of automatically providing a link to the standard MedlinePlus Connect response page
  • Web Service demonstration

Technical Details and Demonstrations

Acceptable Use Policy

In order to avoid overloading the MedlinePlus servers, NLM requires that users of MedlinePlus Connect send no more than 100 requests per minute per IP address. Requests that exceed this limit will not be serviced, and service will not be restored for 300 seconds or until the request rate falls beneath the limit, whichever comes later. To limit the number of requests that you send to Connect, NLM recommends caching results for a 12-24 hour period.

This policy is in place to ensure that the service remains available and accessible to all users. If you have a specific use case that requires you to send a large number of requests to MedlinePlus Connect, and thus exceed the request rate limit outlined in this policy, please contact us. NLM staff will evaluate your request and determine if an exception may be granted. Please also review the MedlinePlus XML files documentation. These XML files contain complete health topic records and can serve as an alternate method of accessing MedlinePlus data.

More Information