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.
Health Benefits of Onions. The health benefits of onions are often overlooked because of their pungent smell and sharp taste and many people prefer to give them a miss. What a shame if that's the case for you! If you want to know what you're missing read on and you might change your mind.