The National Library of Medicine invites you to link from your web site to
ClinicalTrials.gov.
Use of ClinicalTrials.gov data is subject to
Terms and Conditions.
If you link to this site, please provide proper attribution to the U.S.
National Library of Medicine (NLM) and ClinicalTrials.gov.
The data on ClinicalTrials.gov changes nightly. New studies are
published and existing studies are updated every day. To ensure that
the most up-to-date and accurate information is provided to the public,
please do not make static copies of studies or search results.
Instead, use a link to the ClinicalTrials.gov site to preform a new
search or display the latest version of an existing study.
The text below is the HTML for a link to the ClinicalTrials.gov home page.
You can copy and paste the block of HTML directly into your web page.
Please observe the form of the ClinicalTrials.gov name,
which should always include an uppercase C and T, a lowercase g, no space
between "Clinical" and "Trials."
This HTML:
<a href="http://clinicaltrials.gov"
title="Information on Clinical Trials and Human Research Studies">ClinicalTrials.gov</a>
provides patients, family members, and members of the public easy and free access
to information on clinical studies for a wide range of diseases and conditions.
Displays this text in a browser:
ClinicalTrials.gov
provides patients, family members, and members of the public easy and free access
to information on clinical studies for a wide range of diseases and conditions.
Every study in ClinicalTrials.gov has a unique identifier refered to as an NCT Number.
A specific study can be displayed with a link that ends with the NCT Number, like this:
http://clinicaltrials.gov/show/NCT00004451.
If you are looking at a study in ClinicalTrials.gov, the NCT Number can be found near the top and
bottom of the Full Text View
This HTML:
<a href="http://clinicaltrials.gov/show/NCT00004451" title="Study NCT00004451">
Randomized Study of the Effects of Glucose on Cognition in Healthy Young and Elderly People and Parkinson's Disease Patients
</a>
Displays this link in a browser:
Links can be constructed that will search ClinicalTrials.gov.
The results returned are the same as those produced by filling in the Advanced Search form and pressing the Search button.
A specific search can be performed with a link that ends with search terms encoded as URL parameters, like this:
http://clinicaltrials.gov/search?cond=alzheimer's+disease
Standard URL encoding rules apply:
Parameter lists begin with a "?" character and are separated by "&" characters.
Spaces are replaced with "+" characters.
Special characters are replaced with a "%" followed by their ASCII code in hexadecimal.
The following parameters are recognized:
Param |
Purpose |
term |
Generic search |
cond |
Targeted search for conditions |
intr |
Targeted search for interventions |
outc |
Targeted search for outcomes |
spons |
Targeted search for sponsors |
recr |
Restricts search results to open (recruiting or not yet recruiting) or closed (no longer recruiting) studies
Two values are recognized: recr="open" and recr="closed"
|
Additional parameters are recognized, but are more likely to change over time. If you are an experienced HTML developer,
and are willing to risk the possibility that your links will break, inspection of the HTML for the
Advanced Search page will show you what parameters are currently in use.
General search for the term,
pediatric, in ClinicalTrials.gov
<a href="http://clinicaltrials.gov/search?term=pediatric>pediatric</a>
Targeted search for the condition,
Diabetes, in ClinicalTrials.gov
<a href="http://clinicaltrials.gov/search?cond=diabetes">Diabetes</a>
For a multiword term that should be treated as a phrase, spaces must be replaced with "+" characters
and the entire phrase enclosed in quotes, which are URL encoded as %22. For example:
Targeted search for the condition,
Alzheimer's Disease, in ClinicalTrials.gov
<a href="http://clinicaltrials.gov/search?cond=%22Alzheimer's+Disease%22">Alzheimer's Disease</a>
A search with multiple clauses should have the parameters separated by an "&" character. For example:
Targeted search for open studies about treatment of PTSD with the drug,
Fluoxetine, in ClinicalTrials.gov
<a href="http://clinicaltrials.gov/search?recr=open&cond=PTSD&intr=Fluoxetine">Fluoxetine</a>
Targeted search for the sponsor,
NHLBI, in ClinicalTrials.gov
<a href="http://clinicaltrials.gov/search?spons=NHLBI">NHLBI</a>
ClinicalTrials.gov makes it easy for web crawlers to find all studies. Each
time the study collection is updated, pages of links to all studies are generated.
Most users will not find these pages useful.
ClinicalTrials.gov provides data in XML format as shown below.
Please note that use of ClinicalTrials.gov data is subject to our
Terms and Conditions.
-
The simplest way to get data in XML format is to perform a search and use the
download options at the bottom of the search results page. With the download
options, you can retrieve XML for full studies or select fields (e.g. title,
condition, lead sponsor, etc.) from the studies shown in your search result.
The Display Options link, in the upper right of the search results page, lets
you control which fields are shown and downloadable. Downloads produce a zip
file which you can open in your browser or save to disk.
There are two forms of the XML for studies: one which includes the results
information from records that have results and one which does not. Note that
most trials do not contain results information as the results database was
only launched in September 2008 and results information is only required for some
completed trials.
Note that downloads of many studies can take several minutes.
-
The search results list can be obtained in XML format by appending a URL parameter, "displayxml=true",
to the end of a search request URL.
Example:
http://clinicaltrials.gov/search?term=%22lyme+disease%22&displayxml=true
By default, this option will return the first 20 search results.
A parameter, "count=100", can be used to get the first 100 results.
Another parameter, "start=101", can be used to get subsequent sets of studies.
In the following example, all three parameters are used to get results 1201-1400 out of
more than 16,000 results found by a search of "cancer".
Example:
http://clinicaltrials.gov/search?term=%22cancer%22&displayxml=true&count=200&start=1201
Caution: The XML for all studies is about 100 MB in size.
If you attempt to display this much XML in your browser, your browser will probably
freeze for several minutes and then crash.
-
An individual record can be obtained in XML format by appending a URL parameter, "displayxml=true",
to the end of a show study URL.
To include the results data, use the URL parameter, "resultsxml=true".
Example 1:
http://clinicaltrials.gov/show/NCT00001372?displayxml=true
Example 2:
http://clinicaltrials.gov/show/NCT00423098?resultsxml=true
The structure of this XML is defined by this
XML schema..
The
Document Type Definition (DTD)
has been deprecated.
-
A zip file containing a set of protocol records in XML format can be downloaded by
appending a URL parameter "studyxml=true" to the end of search request URL.
To include both protocol and results XML, use the URL parameter "resultsxml=true".
The resultsxml is a superset of the XML. Do not include both parameters.
Example 1:
http://clinicaltrials.gov/search?term=%22lyme+disease%22&studyxml=true
Example 2:
http://clinicaltrials.gov/search?term=lupus&resultsxml=true
Note that downloads of many studies can take several minutes.