Why Onions Make You Cry (And What To Do About It!)

Have you ever been helping in the kitchen, cutting up vegetables, when suddenly your eyes start watering? If onions have ever made you cry, you're not alone! Even professional chefs sometimes get teary-eyed when cutting onions.

But why does this happen? The answer is a cool bit of kitchen science.

The Onion's Secret Defense

Onions grow underground, where they can't run away from hungry animals or insects. Instead, they protect themselves with special chemicals stored inside their layers.

When an onion is whole, these chemicals stay safely separated. But when you slice into an onion with a knife, the cells break open and the chemicals mix together. This creates a gas that floats up into the air.

The gas released by a cut onion travels through the air and reaches your eyes. Your eyes don't like this gas because it can irritate them.

To protect themselves, your eyes make tears. The tears help wash away the irritating gas and keep your eyes healthy. So, even though it feels like you're crying for no reason, your eyes are actually doing an important job!

Why Onions Evolved Like This

You may wonder, why don't other vegetables make me cry? Onions are unusually well-equipped with a chemical defense system. The tear-producing chemicals are thought to be a defense against animals, insects, fungi, and bacteria. The irritating compounds make the plant less appealing to eat and can help protect it from infection after it's damaged.

A Tiny Science Experiment

Next time you're helping in the kitchen, notice what happens when you cut an onion. You might smell the onion first, then feel a slight sting in your eyes, and finally start to tear up. That's your body's natural defense system at work.

Can You Stop the Tears?

You might not be able to stop the tears completely, but these tricks can help:

• Leaving the root end attached while cutting an onion reduces tears because that specific area contains the highest concentration of the sulfur compounds that create tear-inducing gas. Keep the root attached until you're done dicing!

• Chill the onion in the refrigerator before cutting it.

• Ask an adult to use a very sharp knife. Sharp knives damage fewer onion cells, releasing less gas.

• Cut onions in a well-ventilated area so the gas can drift away.

• Wear cooking goggles if you want to look like a kitchen scientist!

Fun Food Fact

Not all onions make people cry the same amount. Some sweet onions contain lower levels of the chemicals that create the irritating gas, so they may cause fewer tears.

Kitchen Science in Action

The next time an onion makes you cry, remember: you're seeing science happen right before your eyes. Every tear is proof that your eyes are hard at work protecting themselves while you create something delicious in the kitchen.