Why do onions make me cry?
One of your facial nerves, called the trigeminal nerve, is responsible for sensations within the nose, mouth and eyes. It can become irritated by acidic or spicy smells or tastes.
The trigeminal nerve can be particularly sensitive to the strong smell of an onion, or even the taste of chilli, and reacts by making tears form in your eyes. Ginger, horseradish and even fizzy drinks can give you the same sort of reaction.
These burning, stinging, biting, prickling and tangy sensations have been part of food around the world for thousands of years, and it seems that the more we eat spicy foods, the more we get to like them.