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Grey literature: Trials registries

What are Clinical trial registries?

Clinical trials in most countries require the person doing a trial to register it in a publicly accessible database. This is highly recommenced by WHO as they believe it is useful in preventing selection and reporting bias as it allows researchers to find out about  other trials and their possibly unpublished results . Knowledge of other trials allows the researcher to avoid unnecessary duplication.

Clinical Trials Registar

Provides a comprehensive database on various clinical trials on a variety of drug and medical equipment. However not all trails have the results available.

Open trails explorer

Provides worldwide access to websites that have information about various trials across several websites. .


Provides a list of British research trials, including the results, which can be searched easily. 

WHO- International Clinical Trials Registry Program

Provides a database where clinical trials funded by WHO can be searched for easily.

Cochrane library

Provides a searchable database of various clinical trials. 

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