July 22, 2015

Why Does Chopping an Onion Make Me Cry?

By: Dr. S. Sharma
Chef Choppig A Red Onion With A Knife

Recently I have often been getting asked the question; “Why do my eyes cry and burn when I cut onions?” Most of us have been there. You’re cutting an onion and start to cry without fail. What is this about you wonder? Here are some facts about the tears you produce when cutting an onion!




When onions are growing, they absorb sulfur from the soil. When you cut an onion, cells are being broken down and their contents are being released.  That makes it possible for enzymes that were kept separate to mix with Sulfenic acid to create a gas that wafts upwards towards your eyes and nose. Sulfenic acid burns and then triggers your eyes to produce more tears to help wash away the irritation.


Types of Tears

There are three types of tears that the human eye produces.

  • Emotional: Produced when you are sad

  • Basal: Are the tears produced to keep the eye moisturized and lubricated

  • Reflexive: Are the defensive tears produced by lachrymal glands to wash away irritation as in the case of cutting onions.


Ways to Minimize Tears:

  • Wear eye protection such as goggles

  • Cut the onion under water

  • Refrigerate the onion before you cut it

Have any burning eye care questions? Give us a call at 780-450-6700 to book your next appointment at Beyond Vision!  Subscribe to Beyond Visions Newsletter to stay updated on the latest promotions, contests and the best tips for healthy eyes and life!

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