Why do Onions Make us Cry?

Ritu Asthana; Illustration by Anup Singh

One of the earliest memories I have as a child is when I was approximately three or four years old. I remember watching my mother work in the kitchen. She was cutting onions for the salad and I could see tears in her eyes. For a child the worst possible thing is to watch his/her mother cry. I got so upset that I got hysterical at my father for causing her pain. For I assumed my father was somehow responsible as we were only the three of us in our family.

Later they explained it to me that it was the onion that was at fault and not my father as I thought. In fact many of us still do not know why onions make us cry - people take it as part of their lives and accept it stoically.

To begin with did you know that you 'cry' all day long? Every time you blink your eye there is a fine layer of water in your eyes. You see, there is a tear gland that is situated over the outer corner of each eye. Every time your eyelid closes, it creates a suction, which takes out some fluid from the tear gland. This fluid we call 'tears'.

Normally this fluid has only one purpose. This is to cleanse the cornea, the white portion of the eye, and so prevent it from drying out. But suppose some irritating substance reaches the eye? The eye automatically blinks and tears instantly appear to wash the irritant out of the eye and protect the eye against the irritant.

We are all familiar with the experience of having smoke get into our eyes. It makes us cry. Well the onion sends out an irritating substance too. The onion has an oil containing sulphur, which gives it its sharp tangy odour. This same substance also irritates the eye. The eye reacts by blinking and by producing tears to wash away the irritant! It is as simple as that.

The onion is an interesting vegetable. It is a member of the lily family, and it is a native of Asia. Onions belong to the genus Alliums and are therefore related to the milder Leek and the very pungent Garlic, both of which are cultivated extensively in Europe. The mildest and the biggest onion is the Spanish onion, which often weighs 450 grams or more.

Man has used the onion as food for thousands of years. Big or small we cannot do without this interesting vegetable even as we start crying at the very thought of cutting it.