Why Do Onions Make Us Cry?

Here’s how the dreaded dinnertime routine of onion chopping brings on the waterworks — and what you can do to dry up those tears.

For a few people, cutting a raw onion is no big deal, but for others, it causes a stinging response that results in tears and mild discomfort.

What’s to guilt for this teary response? Enzymes in the onion that release a powerful gas when you cut into it, and when the powerful gas comes into contact with your eyes, it forms sulfuric acid, which is responsible for that telltale stinging sensation.

“The more powerful the onion is, the more probable it will make you tear up,” says Irwin Goldman, PhD, department chair and professor of cultivation at the University of Wisconsin-Madison.

That means that yellow onions popular in cooking are the greatest culprits, and sweet, mild Vidalia onions are the least likely to trigger tears. Fortunately, onions are the only type of vegetable that causes this crying response, because of their unique sulfur compounds.

So why do onions make you well up, but do not seem to make your co-partner weepy at all? Dr. Goldman says it’s most likely due to the people chemistry of your eyes: Some individuals have little or no response to sulfuric acid, while others have a stronger affectability. And while a few people find that wearing contact lenses reduces their onion-related tears, others may find it makes no difference.

Dry Up Those Onion Tears

To decrease onion-triggered weepiness, Goldman recommends freezing or chilling onions before cutting them up. The cold temperature causes a slower release of the enzymes, which helps reduce your response. “You can also start chopping an onion from the top end — where the skin comes together — instead of from the bottom end, where the stem is,” he adds. Enzymes are more concentrated in the bottom of the onion.

If onions cause you to tear up unnecessarily, consider wearing eye protection when you slice them. “Swimming goggles truly do work,” says Goldman. Or just delegate the chore to another cook in the kitchen.