Hi Londonred, I didn't have a problem with iron causing flares but had a problem with absorbing ferrous sulphate i had been taking them for 3 months when i had a routine blood test i was still aneamic the doc at the hossy said it was because they were sugarcoated and for people like us they tend to go through our systems to quick.I now have iron in liquid form which is better and absorbes quicker into the body hope this helps Bev xx