Is it possible to have developed a lactose intollerance as an adult? I caught a tummy bug off of my DSs last week and it had cleared up and I was feeling back to normal. I don't take much in the way of dairy products but I am partial to a cappuccino. For the first time since the tummy bug I had two cappuccinos today and almost immediately after the second one I was running to the loo. My DS1 had a lactose intollerance as a baby and I was advised to keep him off dairy products for two weeks and it cleared up. I am assuming it is possible for an adult to have the same thing, just wondered if it was possible and would two weeks off dairy be enough for an adult or would it require longer.