[Hazel]

Hazel asked the Naked Scientists:
   Hello Chris and your team
 
Can you explain why, when I choked on a piece of food just now [nothing serious!], my eyes began to water?
 
Hazel
What do you think?

[Chemistry4me]

Coughing or sneezing clears the throat and nose of irritants, while tears clear the eyes.

[Karen W.]

But in this instance the object  or expectorant was caught I her throat not her eyes... I believe that there is a certain amount of pressure at the point air becomes short and th face and eyes strain an are squeezed in an attempt to remove object I think that loss of air etc..may trigger the tear glands pain and instinctual straining for air.....

Then again I am n expert.

[Chemistry4me]

Yes, I think you might be correct. I don't know what I was thinking last time. [][:I]

[thedoc]

Listen to the answer to this question on our podcast.

[Matt McFarland]

The coughing itself isn't the cause of the eyes tearing up. Easily proven:  If I let some saliva go back to the very edge of my throat my eyes immediately water up.  I've done this before just to show people how to tear up on demand.  So that throws the coughing theory right out the window.