WHY ONIONS MAKE YOU CRY?
The action of cutting an onion releases a fine spray of droplets. Recent Japenese research has shown that these droplets contain an enzyme called lachrymatory-factor synthase and sulphur-containing compounds, which react to produce a powerful irritant called Syn-propanethial-S-oxide. When a droplet stikes your eye, you respond by producing a copious flow of tears to try and wash the irritant away.