I read up on enumbers when my son reacted as an infant. Apparently the data shows that blonde haired, blue-eyed boys tend to be more susceptible.
We were on our way back from a holiday in France and stayed at a hotel in St.Malo, we all went out for a meal, where the Chef came out and made a fuss of my son and daughter and gave them a free dessert of ice-cream. After the meal we went back to the hotel and put the kids to bed. Because he was still a tot he was in a cot and we made sure they were off asleep, put a baby mike in the room and went down to the bar to enjoy the last day of the holiday with a bottle of wine.
After a short while we heard shouting and went to the room to check on them, my daughter had shouted at my son. He had bounced and bounced until he vaulted and climbed out of the cot, something he had never done before. He was still a tot. We had to sit and calm him down for ages.
When home we read up on it and got the book "E for E.Numbers" and worked out that it must have been the Vanilla Essence in the ice cream. After that we carefully followed that book for both our kids. One of the worst offenders was in orange juice where they added tartrazine as a colouring.
We made it through, he was always difficult but who isn't as a boy? He is now a huge 6'3" 39 year old with his own daughter.