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.
When chopping an onion, the eyes can water and the nose run; this is precisely why the onion is useful as a healing poultice. Onion can improve circulation and helps break up congestion. The high sulfur content in onions causes thick mucus to move outward toward the skin.