Hi! i have a son who is 18 months. whenever i give him milk he coughs for about 1 hour. why is that? please help.

Probable allergy: Most likely your son is allergic to milk. Food allergies are very common and milk is the most common food allergen. The only real treatment is to not give him milk. Fortunately, he does not need milk to be healthy, in fact he will be far healthier without it. He might be able to tolerate goat's milk, but that is not really needed either.