My son was diagnosed with ADHD and ODD(oppositional defiance disorder) when he was 4. I know that is a really early age for that type of diagnosis, but he would have horrible temper tantrums and bang his head on the floor or destroy everything he could get his hands on. It didn't matter what we did. We thought, at first, he had a touch of autism, but after taking him to a doctor that specializes in pediactric nerology we were told ADHD/ODD was the diagnosis.
He was too young to go on meds so we were assigned an in-home therepist by Family Services. She talked to us at length about diet and how it effects kids. One thing she mentioned was Red dye #40. It was in EVERYTHING. From Kool-aid to jello, and even in some chocolate products. She convinced us to get rid of the dye to see if it made a difference.
It did. We got rid of everything with dye and taught our boy that he couldn't have it. While we still have some issue now and then, the effect of removing the dye was noticable in about 3 days. The temper lessened and he was easier to talk to and even quit getting into as much trouble at school. He is now 8 and we have introduced Red dye #40 a few times to make sure that the results were from taking the dye away. Each time we have given it to him, even in a small dose, and then removed it, it has been several days of horrible tantrums and anger and crying. Once it is out of his system again, he is back to normal.