This article clarifies the use of surgical masks during surgery and the evidence for this. A search performed in PubMed found four studies based on 6.006 patients. The studies described the use of surgical masks in surgery with post-operative infections as endpoint, and the studies had to include a control group. None of the four studies found a difference in the number of post-operative infections whether you used a surgical mask or not. However, the limited numbers of studies make it unsafe to conclude whether or not surgical face masks reduce post-operative infections.