asked
Why do onions make you cry?
The action of cutting an onion releases a fine spray of droplets. Recent Japanese research has shown that these droplets contain an enzyme called lachrymatoryfactor synthase and sulphur-containing compounds, which react to produce a powerful irritant called Syn-propanethial- S-oxide. When a droplet strikes your eye, you respond by producing a copious flow of tears to try and wash the irritant away.
