New Civilization News: Why do onions make you cry?    
 Why do onions make you cry?36 comments
picture 20 Nov 2005 @ 11:29, by Silvia M.S

Who has never cried while cutting an onion? (well, apart from those who have never cut one hehehe). This is a little explanation in easy terms.

Inside the onion cells there are some chemical compounds which contain sulfur. When you cut an onion its cells are broken and those chemical compounds then undergo a reaction that transforms them into a more volatile sulfured products, which are released into the air.

These sulfured compounds react with the moisture in your eyes forming sulfuric acid, which produces a burning sensation. The nerve endings in your eyes are very sensitive and so they pick up on this irritation. The brain reacts by telling your tear ducts to produce more water, to dilute the irritating acid. So you cry to keep your eyes protected from the acid.

There are some tricks to make onion-dicing less problematic:
- Chop the onion under cold water. The volatile sulfured compounds will be released but then they react with the water, instead of reaching your eyes.
- You can freeze the onion for 10 minutes before cutting it. The cold temperature of the onion will slow down the chemical reaction which forms the volatile sulfured compunds.

Versión en español aquí.

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21 Nov 2005 @ 19:38 by jstarrs : You should publish
a scientific book of easy explantions of weirds things like red tomatoes and onions that make you cry, for kids.
And adults.
My mother used to put a spoon or fork between her lips when she cut onions.
Onions skin is also good for putting on a small wound.
It was also used to color material a bright red.
Or was it yellow?
What's good for the memory?

You're right about the dyes. Yellow onion skins can be used to make golden dyes because they have a pigment named quercitin, which is an antioxidant responsible for the onion colour. Red onions give a cranberry red dye, coming from another chemical component called anthocyanin (present also in the beets).

You can play Chemistry in the kitchen and try to make the dye :-):
- Peel the yellow onions and lay out the skins on a cookie tray to dry in a place with good air circulation.
- Put the skins in a nylon stocking and tie the top shut.
- Boil them in a stockpot with 2 quarts of water for 15 to 20 minutes.
- Remove the stocking and voila!!  

22 Nov 2005 @ 14:23 by Enocia @ : Onions
I prefer to see the world as Love. Where there is a realisation that Love is ever present, even in onions, then they can't make you cry; love doesn't hurt.


Personally I prefer option B: I don't cook. :-)

Thank you for your comment, Enocia. Love is ever present, beautiful! I've just read in your blog your trick to cut onions: "You can't fool me onion. I know the One in me is the same One in you." :-)  

26 Nov 2005 @ 03:52 by vibrani : Onions
I don't usually cry while cutting onions, only once in a while does one come along that is quite powerful. One way to avoid the reaction is to slice the onion in half or quarters first with the peel on it. Then remove the peel under cold water.

You're lucky! I always cry while cutting onions. Now I use one of those little devices to chop them: {link:}  

28 Nov 2005 @ 19:28 by khae : Well..
I normally do not cry while cutting onions. And I *do* cook and cut onions, thank you :)

The trick is to wear contact lenses; the iris doesn't get any sulfuric acid, then. Of course, if you do not happen to wear contacts already it's not a very smart solution..

Well, I could buy a pair of those coloured contact lenses and change my look when I'm going to cut onions :-). Or even better, we could invent a kind of contact lenses whose colour changes depending on the concentration of sulfuric acid, so along the process of cutting onions we could get a rainbow in our eyes hehehe.  

5 Dec 2005 @ 17:26 by jstarrs : I just came upon this quote...
..when coming into NCN just now:
Life is like an onion; you peel off one layer at a time, and sometimes you weep.

Great quote! :-)  

4 Jul 2006 @ 10:48 by Johaira Datu-Okho @ : why do onions make me cry?
Dont have informations using scientific method.

The process that takes place when you cut an onion cell, liberating some substances, may be too complicated to explain to non-scientists, as I would need to use many chemical terms. But if you're specially interested, please send me a message and I'll tell you about it :-)  

27 Aug 2006 @ 21:53 by yggfIFKYEf @ : awsome
I didn't now that

Chemistry has many surprises hehehe. Please, have a look to the "Science for everybody" section of my newslog (on the right sidebar) and you will see some other interesting things regarding the chemistry of our daily life :-)  

6 Jun 2007 @ 01:00 by katherine @ : onions
yeah thanks this really helps me because i always tell some one else to cut onions and i wanted to know why they make u cry...
well thankss

18 Oct 2007 @ 17:28 by chrissy @ : onions
they smell weird.
your article thingy is "iite".

wat temperature do you freeze it at?


1 Nov 2007 @ 09:53 by adinarayana mundra @ : chemistry
Iam happy to learn about onions,I cry many times ,now I can overcome with the advice.  

5 Nov 2007 @ 19:58 by Ms.Lausman @ : ok...
Lachrymatory-factor synthase is released into the air when we cut an onion. The synthase enzyme converts the sulfoxides (amino acids) of the onion into sulfenic acid. The unstable sulfenic acid rearranges itself into syn-ropanethial-S-oxide. Syn-propanethial-S-oxide gets into the air and comes in contact with our eyes. The lachrymal glands become irritated and produces the tears! CIAO BELLA!  

5 Nov 2007 @ 20:00 by Ms.Lausman @ : hi

5 Nov 2007 @ 20:00 by Via Matias @ : i dont
i never use onions so im always happy u no cuz i dont cry...  

10 Nov 2007 @ 04:17 by misty @ : Onions
I have been slicing onions for over 20 years with not one tear!! This is done without water or freezer. Most important tip is you must not cut off the bottom of the onion (the root if that's what you'd want to call it). This part of the onion must stay intact!
1st Peal your onion (remember, keep bottom intact)
2nd Slice your onion in half, but it "must" be from top of onion to bottom, not sideways! (from top to root)
3rd Now dice the onion, but very important that the root stays together. What I do is take the knife 'close' to the root and slice the onion horizontaly, than diagnaly without cuting through the root. No tears!!
I wish I could send you a picture of what I'm trying to explain, but I hope you at least try this! I guarantee no tears! Let's just say the onion is the 'root' of our problem! Hope this helps... :)  

19 Dec 2007 @ 18:57 by Alisha Diet @ : projects
im doing a long science research project on the affect of onions on eyes thank for the info! it was helpful :-)  

1 Feb 2008 @ 18:22 by Brooklynn Ayres @ : onions
red onions are to strong, what can we do to change that?  

23 Oct 2008 @ 13:19 by Raquel Patterson @ : onions
We could cut the ends off the sides of the onion then put the onions in cold water to draw out the cells!!!  

3 Nov 2008 @ 22:07 by Billy Gemracker @ : onions
Very interesting.

Why dont other foods do this?  

13 Feb 2009 @ 09:34 by Carla @ : Red onions
Is it true they make you horny?  

27 Feb 2009 @ 00:21 by Brian O' Reilly @ : dry eyes and onion peeling
I have severe dry eyes for the last four years. Will the compounds released by the onions I cut (to try and 'kick start' my moist eyes again) damage the surface of my eyes ? I have tried hundreds of conventional medical drops perscribed by the 'experts'.  

12 Mar 2009 @ 13:19 by Natasha @ : Onions
Now I know why onions makes us cry, thanks for the information!  

14 Mar 2009 @ 14:24 by Whips @ : A cure for the tears created from onions
I have no idea why, but a match held in a person's mouth (Meaning a match sticking out of your mouth kinda like a cigarrette) will allow you to cut an onion with no tears..

Was interesting to find out that the chemicals released had sulphur or the likes of within..  

17 Apr 2009 @ 04:58 by lynn @ :
Good post, thanks.Inside the onion cells there are some chemical compounds which contain sulfur.  

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25 Jun 2009 @ 04:00 by alura @ : Good article
The article is very good.  

28 Oct 2009 @ 13:50 by no no @ : article
its goooooooooooood  

1 Jan 2010 @ 13:29 by audrey @ : resources
im in the 9th grade and im doing a science fair on this and i was wondering where you got your sources from? it would help me out a lot  

12 Feb 2010 @ 11:47 by tracy cajuday @ : comment
it is good to know it.  

12 Feb 2010 @ 12:07 by francing maquiling @ : comment
but somebody told me if you put a bread in youre knife to prevent onoin makes yuo cry.  

13 Apr 2010 @ 17:09 by Me @ : onions
Putting a small spoon in your mouth stops your eyes from watering. I don't understand why. Does anyone know?  

25 Aug 2010 @ 16:16 by pritima @ : onions
when we cut onions why do tears come from our eyes  

13 Feb 2011 @ 04:48 by oslec omotsosirc @ : onions
..hehehe, simple explanation makes me understand it easier..tnx for the info  

11 Jan 2012 @ 00:30 by S @ : onions
thanks for the info:)  

5 Mar 2015 @ 09:27 by istechnology @ : I am very happy to read this. This is th
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9 Mar 2015 @ 06:06 by bestofgaytravel @ : Took me time to read all the comments, b
Took me time to read all the comments, but I really enjoyed the article. It proved to be Very helpful to me and I am sure to all the commenters here! Itâ��s always nice when you can not only be informed, but also entertained!  

30 Mar 2015 @ 06:06 by health-of-migrants @ : well, this is an amazing thing that I fo
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