Why you get tear when you cut onion?

A cut onion releases an irritant into the air which irritates our eyes, the body's response in turn is to try to get rid of the irritant through the production of tears. You can try one of two things to have your eyes water less when cutting onions...one is to cut your onion under a stream of water from your tap, the other is to not cut the end of the onion that has the roots on it...this will result in less irritant being released. kutay