Burger King Onion Rings
Some still have indigestion due to Burger King's onion ringing
I've never had an onion ring served by Burger King, but it's usually due to the fat and is found in the dishes served at Burger King. Sometimes your stomach itches from these ingredients, which can cause stomach upset after eating such foods. You can try taking Zantic or Perilosec to get rid of indigestion.
Onions and indigestion
I work as a cook. Unless you have a sensitive stomach, onion rings do not cause indigestion. The problem may be elsewhere. This is bad for sour because otherwise it is a problem, but the meat itself can go bad. This is the most likely problem (rapid aging).