Why do Onions make you cry?

Question

I was wondering why onions make you cry?

Answer 1

when you cut an onion (break the cell walls) the enzymes in the onions mix with the sulfur compounds in the onions to form a weak sulfuric acid solution - which irratates the eyes.

Your tear ducts start releasing tears to wash the sulfuric acid onion juice out of your eyes.

Answer 2

according to wikipedia,

As onions are sliced, cells are broken, allowing enzymes called alliinases to break down sulfides and generate sulfenic acids (amino acid sulfoxides). Sulphenic acids are unstable and decompose into a volatile gas called syn-propanethial-S-oxide. The gas dissipates through the air and eventually reaches the eye, where it reacts with the water to form a dilute solution of sulfuric acid. This acid irritates the nerve endings in the eye, making them sting. Tear glands produce tears to dilute and flush out the irritant.

Supplying ample water to the reaction prevents the gas from reaching the eyes. Eye irritation can, therefore, be avoided by cutting onions under running water or submerged in a basin of water. Rinsing the onion and leaving it wet while chopping may also be effective. Chilling or freezing onions prevents the enzymes from activating, limiting the amount of gas generated. Using a sharp blade to chop onions will limit the cell damage and the release of enzymes that drive the irritation response.

Answer 3

It is not the strong odor of the onion that makes us cry, but the gas that the onion releases when we sever this member of the lily family.

The onion itself contains oil, which contains sulfur, an irritant to both our noses and to our eyes. Cutting an onion arouses a gas contained within the onion, propanethiol S-oxide, which then couples with the enzymes in the onion to emit a passive sulfur compound. When this upwardly mobile gas encounters the water produced by the tear ducts in our eyelids, it produces sulfuric acid.

In response to the caustic acid, our eyes automatically blink, and produce tears which irrigate the eye, and which flush out the sulfuric acid.

Another reflex to rid the eyes of a foreign substance, that of rubbing our eyes with our hands, often exacerbates the situation, because our hands are coated with the caustic, sulfuric acid producing oil from cutting the onion, which we then rub directly into our eyes.

Much to our chagrin, the only remedy for ridding the onion of its pungent, irritating oil is to boil it, not to slice it or dice it.

Answer 4

When you cut into an onion, you slice through cells which contain
sulfur compounds. Sulfur is quite a noxious (bad smelling)
element. The compounds released are highly volatile, meaning they
quickly enter the air in their vicinity. Your eyes produce tears
because your body wants to wash or dilute the chemicals before they
effect your eyes. The tears are a natural way the body can wash
the offensive chemicals away.

Answer 5

There is a gas released when the onion is broken, that causes you to cry.

Answer 6

have you ever eaten an onion?
it tastes different from every other kind of food.
there's this cell that makes it different sense that's strong so your eyes start to irritate.
It's not like that to some people.

Answer 7

Onions are like animals they have a defence mechanism!!
They spray their toxins so you wont eat them!! lol
No true they use it to save themselves!!

Answer 8

you are cutting into a gas that is released i believe its sulfer

Answer 9

http://www.loc.gov/rr/scitech/mysteries/onion.html

Answer 10

well because it does..... it hurts ur eyez and it burnz them and it makez u tearyy