Why do teachers give students a peppermint before test?

There's no widespread practice of teachers giving students peppermints before tests. The idea might stem from anecdotal evidence or beliefs about peppermint's effects, but there's no scientific basis for it improving test performance. While peppermint has been associated with improved alertness and concentration in some studies, these studies haven't definitively shown a link to improved test scores. Any perceived benefit is likely placebo effect.