Why Onions Make You Cry and What You Can Do

On March 5, 2024 by Tim Newman
Why do onions make you cry?

Dry your eyes, mate

Anyone who’s ever sliced or diced an onion will know it can be an emotional and slightly painful affair. What’s going on, and can you prevent these veg from making you cry?

In short, onions release defense chemicals to stop predators — like you — from eating them.

When you chop into their cells, chemicals spill out and start interacting with each other. This generates other compounds, including a lachrymatory factor (LF).

The LF drifts up to your eyes, irritates them, and your tears flow freely to dilute and wash it away.

If the stinging sensation associated with cutting onions makes you feel revived and energized, you can stop reading now. But if you’d like some tips on reducing the burn, read on.

Halting the hurt  

As you might have guessed, there hasn’t been much scientific research into reducing onion eye-burn. 

So, the following hacks may or may not work, but they’re worth a shot.

  1. Wear swimming goggles. It’s obvious how this might work, and it’s a bold fashion statement.
  2. You can try “Sunions.” Their producers explain they’ve spent 30 years cross-breeding onions to create a tear-free chopping experience.
  3. Cool the onion first. The argument goes that less tear-inducing chemicals will enter the air and, therefore, your eyes.
  4. Chop the onion under the fume hood of your cooker. Hopefully, the fumes will whizz past your eyes and into the vent.
  5. Chop the onion under a running tap. This could help stop the onion chemicals from reaching your eyes. But it sounds slippery and dangerous. So if you try it, be careful, please.
  6. Use a sharp knife. It will, theoretically, disrupt fewer cells and spill less of their troublesome chemicals. 
  7. Chop next to a fan or an open window with a breeze. If the fumes are blown away from you, they can’t bring you to tears.
  8. Hold a piece of bread in your mouth. Some believe the bread will absorb the stinging vapours before they reach your eyes.

I hope at least one of these will help. Let me know how you get on please.

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