Anyone who has ever cut an Onion knows the familiar sting that can bring tears to your eyes. Fortunately, a few simple kitchen tricks can help make onion chopping much more comfortable.

Why Do Onions Make Your Eyes Water?

When an onion is cut, its cells are damaged and release sulfur-containing compounds into the air.

One of these compounds, known as propyl sulfoxide, reacts with moisture in the air and around your eyes to form an irritating gas. Your eyes respond by producing tears to wash the substance away.

If your eyes begin watering while cutting onions, avoid rubbing them with your hands, as this can transfer more of the irritant directly into your eyes.

2 Things to Remember

1. Chill the Onion Before Cutting

Placing onions in the refrigerator for at least 30 minutes—or in the freezer for 10 to 15 minutes—slows down the enzymes responsible for releasing the irritating compounds.

This is one of the most effective and widely recommended techniques.

2. Use a Very Sharp Knife

A sharp knife slices cleanly through the onion’s tissues, causing less cell damage and reducing the amount of sulfur compounds released.

A dull knife crushes the onion and can make the irritation much worse.

1 Thing to Avoid

Don’t Cut the Root End First

The root end of the onion contains the highest concentration of sulfur compounds.

Professional chefs often cut off the top first, peel the onion, and leave the root intact until the very end to reduce exposure to the irritating gas.

Additional Tips to Reduce Eye Irritation

• Turn on a small fan to blow the vapors away from your face.
• Cut onions under running water or in a bowl of water.
• Rub a slice of raw potato on both sides of the knife.
• Chew gum or hold a piece of bread in your mouth to encourage mouth breathing.
• Lightly wipe the cutting board or knife with white vinegar.
• Wear protective glasses or even swim goggles for extra protection.

The Bottom Line

The easiest way to cut onions without tears is to remember three simple rules:

1. Chill the onion before cutting.
2. Use a sharp knife.
3. Avoid cutting the root end first.

With these small adjustments, preparing onions can become much more comfortable and enjoyable.