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.
Chill the onions in the freezer for 10 to 15 minutes before cutting them. This reduces the amount of the acid enzyme released into the air and has zero effect on taste. This was found to be the most effective way to reduce tears by the television program Food Detectives.