Go to a doctor now if: Poor growth, blood in stool, vomiting, swelling or breathing trouble with milk (possible milk ALLERGY — needs a doctor), or ongoing pain despite adjusting dairy — get a medical/growth review.
Food-first comfort
Offer smaller amounts of dairy with meals rather than alone; curd/yogurt and paneer/cheese are often better tolerated than plain milk (their bacteria/processing reduce lactose); ensure calcium from non-dairy foods — ragi, sesame (as powder/laddu for older kids), green leafy vegetables, small soft-boned fish; keep total nutrition varied.
What to nourish
Curd, buttermilk, paneer, ragi, sesame, greens, and other calcium foods so bones stay well supplied.
Never
Don't remove ALL dairy and calcium foods without replacing the calcium (and without a doctor for young children). Don't confuse intolerance (tummy discomfort) with a true milk ALLERGY (which can cause swelling/breathing trouble and needs medical care).
Care at home
Lactose intolerance is about comfort with the milk sugar, and small adjustments usually help while protecting calcium. True milk allergy is different and must be assessed medically.
Related guides
When to see a doctor. Children are not small adults. This guide offers food-first comfort for a parent to consider; it gives no medicines, doses or supplements for children. A paediatrician decides on treatment. When in doubt, go.