My son vomits maybe once a week. We ve switched him to lactose free milk after complaining of stomach gas from regular milk. He loves cheese products and we give him yogurt every day. He was treated for walking pneumonia recently and still has a cough in the morning as well as congestion. My son otherwise if fine - healthy appetite, no fever, regular activity level. Don t know why he vomits like this. Maybe also feel we try to feed him too much because he s thin.