Every year, up to 12 million kids bring home head lice. Many of the usual treatments contain pesticides, make lice resistant to the chemicals they contain, or simply don’t work. Now comes new hope: A prescription lotion called Ulesfia, which suffocates the bugs instead of poisoning them—a super-charged version of the classic slather-on-the-mayonnaise approach. But lice can survive being coated with mayo for hours by closing their breathing apparatuses. Ulesfia prevents this, so lice asphyxiate within minutes—a method that lice are less likely to become resistant to. You’ll still need to treat twice, though—once to kill live lice and again about a week later to catch any that have hatched from the eggs.