As anyone who’s ever mixed up the sugar and salt while baking knows, too much of a good thing can be inedible. What hasn’t been clear, though, is how our tongues and brains can tell when the saltiness of our food has crossed the line from yummy to yucky — or, worse, something dangerous. Now researchers report that in fruit flies, at least, that process is controlled by competing input from two different types of taste-sensing cells: one that attracts flies to salty foods, and one that repels them.