At first it was thought to be an onion allergy, but that does not seem to be the case
. It comes on for no apparent reason. I've been hospitalized several times, had all kinds of tests - CAT scans with and without contrast and dye, blood work, etc. etc. They've ruled out kidney stones, gallstones, appendix, ovarian cause, growths, etc. But the pain is so severe that I faint. It can last anywhere from 1/2 hour to many hours. Sometimes, Gas-x and advil seem to help.