I find yellow food colourings effects her the most and maybe some flavourings. I have to be careful with yoghurts, custards, icecreams and even breakfast cereals. I can't even give her Nurofen for babies, it hypes her, not good when she is sick. I spoke to a Pharmacist and she thought it could be the flavouring that is causing it.

It is different for everybody though. The failsafe diet (I think there are already threads about it on here), lists the possible additives, foods etc that could cause problems. Some people have to eliminate them all, others just 1 or 2.