My eldest in particular used to vomit a lot as a baby and every time he got a cold he would vomit too. He wasn't a good eater either so starting giving him a probiotic yoghurt drink with a straw as a treat!! I found that his health and appetite improved and continued these with my younger son too and they are both really robust kids that are seldom sick. my eldest is looking at his 5th school year without and absence and he is only 11 now and youngest has 4 years and is a year younger. So, i'm convinced.