Why slicing onions brings tears to your eyes.

Why you cry when slicing onion.

Ever wondered why tears flow from your eyes uncontrollably almost every time you slice onions? Here’s why.

  • Onions use sulfur in the soil to create amino acid sulfoxides.
  • These sulphur compound then turn into a gas.
  • When an onion is cut open, it releases the sulfoxides and enzymes, which react and create a gas called syn-propanethial-S-oxide.
  • This gas gets into the air, comes in contact with the eyes and causes the Lachrymal gland to become irritated and produce tears.
  • Some onions such as the white, yellow and red onions have a higher concentration of onion enzyme necessary to create this gas, while sweet onions, green onions, and scallions have lower concentrations.

Don’t worry about the big words, what makes you cry is the gas that the onion produces. This gas causes irritation to the eyes, and your eyes respond by trying to flush the gas away with tears. You can read more about tears in my previous post, click here to see.  Or click here

So the next time you feel those tears flowing out, don’t try to stop them, just know it is your eyes way of flushing out this gas in order to protect them.

Some are of the opinion that slicing onion inside a bowl of water can also prevent this gas from getting to you. You can try this.

Or better still, you can wear a safety google when slicing.