I Wonder Why – Why Onions Make Me Cry?

Why do onions make you cry?

● When you slice through an onion, you break open several onion cells. Some 

of these cells have enzymes inside of them, and when they are sliced open, the 

enzymes escape.

● The enzymes then decompose some of the other substances that have escaped 

from sliced cells. Some of these substances, amino acid sulfoxides, form sulfenic 

acids, which then quickly rearrange themselves into a volatile gas. 

● The gas reaches your eyes and reacts with the water that keeps them moist. This 

changes  the  chemical’s  form  again,  producing,  among  other  things,  a  mild 

sulfuric acid, which irritates the eyes. The nerve endings in your eyes are very 

sensitive and so they pick up on this irritation.

● Peeling  the  onion  and  then  chilling  it  in  the  refrigerator  before  you  slice  it  will 

minimize the release of gas.

● Another easy solution is to cut the onion under water or run the tap over it as you 

slice.