General Knowledge · 2
Why do onions make you cry when you cut them?
Answer
They release a chemical irritant called syn-propanethial-S-oxide
Cutting onions releases sulfur compounds, particularly syn-propanethial-S-oxide, which reacts with the moisture in your eyes to form a mild sulfuric acid. This irritates the eyes and triggers tear production as a protective response.
💡 Did you know?
Chilling onions before cutting slows down the release of these tear-inducing chemicals, reducing eye irritation.
Other options people guess
- Onion juice is acidic and burns your eyes
- The smell triggers tear production
- Onion cells contain capsaicin like peppers
Topics
- chemistry
- biology
- cooking
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