My gluten/casein reactions last anywhere up to 14 days. It doesn't relate to the amount I consumed either,they just seem to get steadily worse each time. They used to last a day, then 2, then 3, then 5, then a week, then 10 days, then the last time it was a solid 2 weeks. This was from one small taste of egg that had been mistakenly fried in butter...