Open-label trial

Template:Short description An open-label trial, or open trial, is a type of clinical trial in which information is not withheld from trial participants.<ref name="nci">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> In particular, both the researchers and participants know which treatment is being administered.<ref name=nci/> This contrasts with a double-blinded trial, where information is withheld both from the researchers and the participants to reduce bias.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Open-label trials may be appropriate for comparing two similar treatments to determine which is most effective, such as a comparison of different prescription anticoagulants,<ref name="beyer">Template:Cite journal</ref> or possible relief from symptoms of some disorders when a placebo is given.<ref name="ballou ">Template:Cite journal</ref>

An open-label trial may still be randomized. Open-label trials may also be uncontrolled (without a placebo group), with all participants receiving the same treatment.<ref name=beyer/>