Researchers discovered that hydrogen sulphide (H2S), a small gas molecule, can effectively kill the fungi and bacteria that cause painful nail infections. Unlike current treatments that struggle to penetrate into the nail, hydrogen sulphide easily diffuses through the nail plate. The study found that H2S works by damaging the fungi’s respiratory system and creating harmful reactive oxygen species, while also modifying proteins in a way that disrupts their normal function. This innovative approach could offer patients a new topical treatment option for nail infections that have been difficult to treat with existing medications.