Why we get tears when we cut onions? Which chmeical brings tears?

What is tear gas? Generally people use onion to reduce irritaion when exposed to tear gas? How does onion help?

 

Thabks

there are Many lacrymator agents out there under the name of "Tear gas" regular Bleach is the best neutralising agent for most of them (if you`re crazy enough to pick the canister up and happen to have a bucket of bleach handy to drop it in).

 

Onions contain Sulpher based agents that give the tear effect.

 

one of the best natural products is alyl isothiocyanate from Horseradish, that stuff isn`t funny

How does onion help?

Is there any evidence that onion does help?

Inside the cells of a onion are several organic sulphuric compounds, among them is aliine, an amino-acidsulfoxide.

When you cut or crush the tissue this compound together with enzymes called allinases are released and convert alline to a sulfonic acid. The sulfonic acid is then converted to propanethio-S-oxide.

Next step propanethio-S-oxide forms sulfuric acid when it reaches through vapour the moisture of your eye which irritates your eyes, so they produce tears to get rid of the acidic substance. Thiosulfinates (sp?) are also formed which gives onion a strong smell.

 

So when you cut onions, this is why they make you cry.