Background: There is a problem with the visibility of retractions, and many retracted papers continue to be cited as if they were still valid. It has been suggested that authors citing retracted papers should be contacted about it, but this has been deemed too challenging and has never been attempted.

Design: This is a randomised controlled trial.

Methods: All eligible retracted papers will be randomised either to the intervention (an email notifying authors of the citing papers about the fact that they have cited a retracted publication) or the control group (no notification email).

Outcomes: The primary outcome will be the rate of citation of retracted papers during 12 months follow-up. The secondary outcomes will be a 24-month follow-up and the qualitative analysis of feedback from the authors in response to the intervention email.

Conclusions: Our trial will investigate whether the number of citations of retracted papers can be reduced by notifying researchers that they cited a retracted paper.