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.
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.
Cover it with a lid and refrigerate. I've had a cut avocado stay fresh for several days this way. I don't know why this is, but I suspect that it has to do with the sulfur compounds that the onion releases. This is the same sulfur that makes you cry when you chop onions, but it is also used as a preservative.