Why do onions make you cry? Onions are made up of a tunic of outer leaves (the brown layer), scales (the white firm juicy edible part), and the basal plate (often called the “hairy part” or the “root”). Onions make you cry because:
1. When you cut the basal plate or shoot, they release an enzyme.
2. That enzyme reacts in the rest of the onion to release a gas.
3. When that gas combines with water, it creates an acid.
4. If that water is in your eye, you have acid in your eye. That makes you cry.So, if you still want to cut some onions, there are some simple steps that keep you tear-free!

Before cutting an onion rinse the onion under cold water. 

You can also stick the onion in the freezer for a 10 – 15 minutes before cutting it.

Breath through your mouth and not your nose.

Put vinegar on your cutting board.

Use a very sharp knife.