Why Do Onions Make You Cry?

Are onions mean bullies that like to make us cry? Or is there more to an onion? Those tricky, tricky, onions.

Cyrus and Katarina get to the bottom of an onion’s secret powers and why we react to them like crybabies. And let’s not forget about the onion’s feelings too… poor onions.

When We Cut Into an Onion…

Cutting an Onion

Cutting an Onion

The onion’s cells and insides break open and mix together. This mixing together of the onion’s juices creates a sulfuric gas. This sulfuric acid has a long name so get ready, okay? It’s called:


syn-Propanethial S-oxide

syn-Propanethial S-oxide AKA: ‘Ol Synnie Poo!

Ol’ Synnie-poo, we like to call him, rises into the air from the sliced onion and eventually reaches our eyes. This is where it gets kind of crazy!

When Ol’ Synnie-poo meets our eyes, a chemical reaction occurs. Our eyes have a thin layer of water over them because they need to stay moist so they don’t dry out. Well, Ol’ Synnie-poo combines with the water in our eyes and creates…

Sulfuric Acid!

Yep! That’s right. Ouch! Nobody wants sulfuric acid in their eyes because it hurts. This is the stinging feeling you may feel when cutting onions. But don’t fret, our body is a highly resilient and complex machine.

Lacrimal Glands Producing Tears

Lacrimal glands above our eyes produce tears

Lacrimal Glands

Which are just above our eyes, send tears to our eyes. These tears flush the sulfuric acid out of our eyes, which is what leads us to cry. The tears flood our eyes and take the sulfuric acid with them.

And This Is Why Onions Make You Cry


An onion has struck again!

How to Prevent Onions From Making You Cry

  1. If you refrigerate onions before cutting them, the onion’s juices don’t mix together as quickly and less sulfuric acid is released
  2. Wearing glasses or a mask can prevent ‘Ol Synnie poo from reaching your eyes
  3. Cutting onions in water washes away the onion’s juices before they can mix together and prevents the release of the sulfuric gas

But Let’s Not Forget About the Onion

Why Do Onions Cry?

Why Do Onions Cry?



Why Do Onions Make You Cry?

Executive Producers
Jim Demetriades and Nikos Iatropoulos

Directed by
Luke Gschwend and Joseph Rohrs

Hosted by
Cyrus Rohrs and Katarina Demetriades

Written and edited by
Luke Gschwend

Production Assistant
Gwynne Rohrs

Title Animation
Jonathan Reaux





Music Licensed through Audiojungle: “Cheeky” by SASMusic


  • www.pbs.org/newshour/rundown/why-do-onions-make-us-cry
  • www.positivemed.com/2014/02/25/onions-make-cry-avoid

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