Why Onions Make You Cry & How To Stop It

Added: 2026-06-05

[00:00:00]From the humble kitchen counter, a seemingly simple vegetable holds a complex chemical defense that brings tears to our eyes.

[00:00:07]We often blame the fumes for the burning sensation, but the true culprit is a rapid enzymatic reaction happening on a microscopic scale.

[00:00:16]When an onion is cut, its cells rupture, releasing a sulfur-rich compound called propanethial S-oxide, which is then converted into a potent lacrimal toy factor.

[00:00:26]This volatile gas quickly disperses into the air, reaching our eyes and reacting with the water on their surface to form sulfuric acid, triggering the stinging and tearing.

[00:00:37]However, a simple trick like chilling the onion for 30 minutes before cutting can significantly slow down this enzymatic process, reducing the release of the tear-inducing compounds.