URL of this page: https://www.nlm.nih.gov/medlineplus/connect/technical.html

MedlinePlus Connect: Technical Information

MedlinePlus Connect is available as a Web application or a Web service. Please tell us if you implement MedlinePlus Connect by contacting us.

If you are interested in using MedlinePlus Connect or have implemented it, sign up for the 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.

Web Application

The MedlinePlus Connect Web application responds to requests with an on-demand, formatted MedlinePlus Connect Web page. This page provides some basic information and links before the patient goes to the full MedlinePlus page(s).

Web Service

Using the MedlinePlus Connect Web service, a patient portal or EHR 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.


MedlinePlus Connect allows any health data system, including patient portals, patient health record (PHR) systems, and electronic health record (EHR) systems to link to MedlinePlus information using standard clinical vocabularies.

  • A PHR or 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.

See our list of some MedlinePlus Connect users.

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 until the request rate falls beneath the limit.  To limit the number of requests that you send to MedlinePlus 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.  

More Information

In addition to MedlinePlus Connect, NLM also provides XML files and a keyword query-based Web service as additional sources of MedlinePlus data in XML format. For more information on how to link to MedlinePlus content, please see our guidelines and instructions on linking.