There are many reasons to love nonstick cookware. It lets you cook with less fatty butter and oil, and is easy to clean. But there’s a downside. The flouropolymer coating that gives the pans their nonstickiness can release chemicals when it gets hot—including perfluorooctanoic acid, a carcinogen. There’s even an illness called “teflon flu” that you can get from inhaling the toxic fumes. To protect yourself, don’t preheat your nonstick pots and pans at a high temperature and try to cook over a low to medium flame.