Never Cry While Cutting Onions Again—This Science-Backed Trick Actually Works

I was standing at the kitchen counter preparing dinner. Tears rolled down my cheeks. I sniffled and attempted to wipe my eyes with my sleeves. I wasn’t crying over spilled milk, nor was I crying because of a broken heart. I was crying because I was chopping an especially pungent onion—one with an aroma so powerful you could smell it across my apartment. So many recipes start with onions that if you cook at all, you’ve undoubtedly experienced the unpleasant, tear-inducing effects of an onion. But why does this happen, and is there any way to minimize the vegetable’s irritating effects on our tear ducts?

When onions experience cell damage—such as when they’re cut—their cells release alliinase, an enzyme that produces sulfur compounds. In his book On Food and Cooking, food science writer Harold McGee notes that this is the vegetable’s defense mechanism. According to McGee, plants “compensate for their immobility with a remarkable ability for chemical synthesis” and “produce thousands of strong-tasting, sometimes poisonous warning signals” to discourage predators from attacking them. Those sulfur compounds released by the onion are intended to “annoy and repel” their attackers by irritating their mouths, nasal passages, and eyes.

These compounds are especially potent at room temperature. In his cookbook Veg-Table, Serious Eats contributor Nik Sharma writes, “The enzyme alliinase produces its most potent chemicals at warmer temperatures; cold temperatures will reduce the activity of this enzyme.” So to minimize the tear-inducing effects of an onion, Sharma simply refrigerates his onions for an hour or two before using them.

I read about the method in Veg-Table shortly after the book was released in 2023, and was curious to test it out myself—so I refrigerated an onion for an hour before slicing it. Miraculously, I did not shed a single tear. Although I was skeptical, I am now a converted believer who will never cut an onion without first refrigerating it. I should note that this is entirely anecdotal; I have not scientifically or methodically tested it against other techniques, but in my personal experience, it has proven to work extremely well. Onions may have once annoyed and repelled me, but thanks to this simple trick for reducing kitchen tears, they no longer do.