Why Onions Make Your Eyes Water

Are you a food enthusiast? Do you love creating delicious art in the kitchen? I’m a pretty neat chef, if I may say so myself. However, if there’s one thing I simply hate doing, it is cutting onions. Unless you’ve never cooked anything in your life, you probably have had an experience of the burning sensation and tearing while cutting onions. I’ve constantly found myself looking for ways to avoid this horrid experience and I’ve finally worked it out. To solve this issue, you need to understand exactly why onions make your eyes water. Only then can we move on to finding the right solution.

How Do Onions Make You Cry?

Of course, you must be aware of the pungent juice coming out of onions. It is common knowledge that this misty juice is responsible for tearing your eyes up. However, what exactly does this juice contain to have such a powerful impact on you? Lachrymatory factor in onions is responsible for making your sensitive eyes water.

Lachrymatory Factor

The lachrymatory factor essentially causes irritation in your eyes which leads to the stimulation of tear glands. Think of the mechanism as that of a tear gas. The gland that regulates tears in your eyes is known as the lachrymal gland and it can be found right above your eyelids. Once your eyes are irritated by any external source (onions), your brain receives a message. As a response, your brain makes an attempt to flush this irritant out by overworking the glands.

Amino Acid Sulfoxides

Onions contain high levels of Sulfur and once you chop them, they release certain enzymes. The sulfur from the onions reacts with amino acids and Amino-acid sulfoxides are formed. These are known as syn-propanethial-S-oxide compounds. These compounds are released in the air due to their light weight and get caught in your eyes causing severe irritation. This compound is the primary reason as to why onions make you cry.

However, this process holds true only for raw onions. In the case of cooked onions, the enzymes become inactive and hence, the syn-propanethial-S-oxide is not created. This is why you have no issues of tearing up while chewing cooked onions.

Tearless Onions

If you’re still unaware of the glory of sweet onions, you’re in for a pleasant surprise. Sweet onions are a tearless option. I tend to cook with these when I simply cannot take the pain of constantly tearing up while chopping onions. Vidalia is a type of sweet onions and it is free of any sulfuric compound as these are especially produced in a soil that is deficient of sulfur. The lachrymatory factor is hence not produced along with any other compounds that create the hot flavor or pungent smell.

Best Ways to Prevent Irritation From Onions

Now that you know why onions make you tear up, it’s time to unravel different tips I find super helpful while using onions in my cooking. You can try all of these and stick with whichever works most effectively for you.


Prior to cutting your onions, simply refrigerate them for at least thirty minutes. The reaction rate of enzymes with sulfoxides is slowed down with the cooling process. This leads to minimal production of syn-propanethial-S-oxide. You might still be able to experience mild irritation, but the tip should most definitely make the experience pleasant.

Turning the Fan On

Sometimes simple steps such as turning your fan on, work as well. By turning the fan on in the opposite direction, you can simply direct the irritants away from you. This process is not as effective in the case of a ceiling fan.

Running Water Over Onions

You can try running water over the onions while cutting them. The compounds responsible for the irritation are water soluble and can simply be washed away instead of allowing them to get in the air. You might have to be speedy with the process as the irritation begins as soon as you start cutting the onions open.

Using Water Goggles

As I am quite finicky about cutting onions, I sometimes prefer to use water goggles. As silly as that might sound, these work quite effectively for me. The goggles basically stop the vapors from entering my eyes and I am able to finish the cutting in no time.  If you like to goof things up a bit, this is a fun way of stopping your eyes from tearing up.

Final Thoughts

This sums up all you need to know about why onions make your eyes water and simple ways to stop them from doing just that. I hope this information is helpful in creating a better cooking experience. Do you have any effective tips to share? Don’t hesitate to tell us. Comment if you have any questions regarding the tips.