Editing peer reviewsThe COPE guidelines “Editing peer reviews“ are intended to advise editors, publishers, and researchers on expected practices and appropriate circumstances regarding the editing of peer reviews. The guidelines look at the need for journals to amend peer reviews, and provide insight into situations where this might be an appropriate course of action. Journals should have clear policies on what is acceptable and unacceptable in a reviewer report regarding tone, language, and content, and advice on the extent to which a review can be edited to adhere to these policies. There are alternative methods for editors to deal with controversial content, and advice is given on how to respond to hostile or unprofessional reviews.