Why do onions make us cry?

Onions come in many varieties and three main colours — yellow, white and red. They are rich in nutrients including vitamins B and C, protein, calcium and iron.

It’s not the strong odour of the onion that makes us cry, but the substances that are released when we chop it. The vegetable contains some sulphur compounds which are released when we cut it. Sulphur, being an irritant to both our nose and eyes, makes our eyes tear up.


What actually happens when the sulphur compound comes in contact with the water in our eyes is this — it produces very dilute sulphuric acid. This acid then irritates the eyes. In response to this acid, our eyes automatically blink and produce tears, which wash the eye and flush out the acid.

An automatic reaction many people show is to rub their eyes with their hands. This often makes the situation worse, as our hands are covered with the sulphur compounds, which we then rub directly into our eyes.

The only remedy is to boil the onion, not slice it. But this is not a very practical solution. Some people suggest putting the onion in the freezer for a few minutes because the cold decreases the speed of the chemical reaction. Another tip is to slice the area around the root last, as this contains more sulphur.

British farmers have developed the new kind of onion, called Supasweet onions. It is said to be so mild that it can be eaten like an apple. Supasweet onions have been available in supermarkets around England since 2003. The onion has a pale, thin skin, is easy to peel and quick to prepare. These onions are not genetically modified. Their secret is that they have been specially grown in low-sulphur soils!

Source:The Telegraph (Kolkata,India)

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