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Fact Sheet

What is is a web site that provides patients, family members, health care professionals, and other members of the public easy access to information on clinical studies on a wide range of diseases and conditions. Information is provided and updated by the sponsor or principal investigator of the clinical study and the web site is maintained by the U.S. National Library of Medicine (NLM) at the National Institutes of Health (NIH).

How do I find is available on the World Wide Web from the NLM Home Page ( or directly at (

What information is in

Summaries of Clinical Study Protocols that include the following information:

  • summary of the purpose of the study
  • recruiting status
  • disease or condition and medical product under study
  • research study design
  • phase of the trial
  • criteria for participation
  • location of the trial and contact information

Summaries of Clinical Study Results for some studies that include the following information:

  • description of study participants (e.g., number enrolled, demographic data)
  • overall outcomes of the study
  • summary of adverse events experienced by participants

Links to Online Health Resources that help place clinical studies in the context of current medical knowledge, including MedlinePlus® and PubMed®.

Why has the National Institutes of Health (NIH) established
The information resource was initiated as a result of the Food and Drug Administration Modernization Act of 1997 (FDAMA). The law requires the Department of Health and Human Services, through the NIH, to establish a registry of clinical trials for both federally and privately funded trials "of experimental treatments for serious or life-threatening diseases or conditions." was expanded in 2007 after Congress passed the Food and Drug Administration Amendments Act (FDAAA).  This law requires more types of trials to be registered (e.g., certain medical device trials); additional trial registration information (e.g., primary outcome measure); and the reporting of summary results, including adverse events, for certain trials.  The law also established penalties for non-compliance.

How is study information submitted to
Study sponsors or principal investigators submit clinical study information using NLM's Protocol Registration System (PRS), a Web-based tool for submitting information to Information regarding registering a study and reporting results may be found at Organizations that are responsible for registering a study must have a PRS account before submitting data ( facts

  • Completely confidential to search. No registration or personal identification is required.
  • Includes over one hundred thousand completed and ongoing studies funded by the U.S. NIH, government agencies, industry, and universities, foundations and other organizations from around the world.
  • Released February 29, 2000.

Need more information?
NLM's toll-free number is 1-888-FINDNLM (1-888-346-3656) 
NLM's e-mail address is

A complete list of NLM Fact Sheets is available at:
(alphabetical list)
(subject list):

Or write to:

Office of Communications and Public Liaison
National Library of Medicine 
8600 Rockville Pike
Bethesda, Maryland 20894