Covid-19 is a serious illness. Deaths are rising steadily, and health systems are under strain. While most countries are following international health recommendations to wear face masks during the covid-19 pandemic the situation has been complicated in Sweden. Officials in Halmstad municipality, Sweden, forced a teacher to remove their mask and prohibited the use of masks and all forms of medical face masks in their schools. The municipality said there was no scientific evidence that wearing masks offered protection, citing the (...) Swedish Public Health Agency. At the time, agency guidance stated that there were "great risks" that masks would be used incorrectly. This guidance has since been removed. To someone unfamiliar with the Swedish response to the covid-19 pandemic, this mask ban might sound appalling. Especially since growing evidence indicates that face masks possibly do help reduce the spread of covid-19, especially in situations where maintaining distance is impossible. This essay is asking the ethical question if policy makers should apply the precautionary principle and encourage people to wear face masks on the grounds that lives potentially could be save. (shrink)