To mitigate the tear-inducing chemical that onions release when the skin and layers are crushed, keep the root on the onion while you cut. When crushed, onions release propanethial-S-oxide as a defense mechanism to deter predators, which is why you should avoid hurting the root as best you can.

In a tutorial for dicing an onion, Gordon Ramsay explains this phenomenon saying, “This is the root [...] if you cut that off the onion will start to bleed and you will start crying rapidly.” Leaving the onion’s roots on can also help you cut precisely and safely because the layers stay on and make it easier to control the onion.

Ramsay advises keeping three fingers on top of the onion and allowing the knuckle of your front finger to guide the knife to cut across the onion with the knife tip facing the root but not past it. Ramsay then suggests “gripping the onion like a tennis ball,” which produces better pieces and keeps the knife stable.