1 Pain that does not diminish with rest, and pain that may be worse at night than during the day. 2  Back pain along with constitutional symptoms, such as loss of appetite, unplanned weight loss, nausea, vomiting, or fever, chills or shakes.
Unstable chemicals. Onions produce the chemical irritant known as syn-propanethial-S-oxide. It stimulates the eyes' lachrymal glands so they release tears. Scientists used to blame the enzyme allinase for the instability of substances in a cut onion.
How to Prepare Onions for Dehydration. Step One: Peel and cut off the ends of the onions you want to use. If the onion irritates your eyes and nose, then put it in the freezer for 20 minutes before slicing. Use the ends for broth, or add to your compost pile.