This Cochrane review shows that compared with no face mask use, wearing a face mask may make little to no difference in how many people that catches a flu‐like illness. It probably makes little to no difference in how many people that have flu confirmed by a laboratory test. Unwanted effects are rarely reported but include discomfort. Furthermore, it may seem that it makes little to no difference what type of face mask is used. This review searched for studies in April 2020 and does not include studies on COVID‐19.