My son is 3½ and about a year ago, he started vomiting after drinking milk or eating something with large quantities or milk. We took him to the doctor thinking that he could be lactose intolerant, but all of the tests came back negative. The doctor did say that they weren't always conclusive but to slowly reintroduce normal milk into his diet. The first time he drank real milk he vomited and since then, he has been on lactose free milk. My question is that sometimes (more often than not, actually) that his bowel movements are very loose - not diarrhea, but not solid either and they are always the same light brown colour. Could some kind of allergy be causing this or something else? He does eat products, such as cheese and yoghurt, that are not lactose free and he does complain of a poorly tummy on occasion, too.