Landon had problems with lactose, but not that way, it instead made him really constipated. We switched him to lactose free formula until 6mo and then tried regular stuff and he was fine, he's 6 now and never had a problem since. Hayden had a dairy intolerance, he never tested for it as an allergy but his body could not handle it or a few other things. He was breastfed though, but everytime I drank milk he reacted. We started introducing foods with it at around 16mo and he finally stopped reacting (we had tried many times before with no luck) he's 20mo now and he can have milk, though if he has too much he will vomit or break out, but he can handle 1-2 cups a day and cheese and stuff like that. It's like his body has a limit on what it can have when it comes to dairy, soy, bananas, tomatoes and avocadoes...it's really weird. But for the most part he's outgrown it. Our dr said that most babies do outgrow it by age 1, those who don't usually will by age 3, it's more common for them to outgrow it then to stay with them, but usually if they haven't outgrown it by age 3 it is something they will always have