Can babies have ibuprofen?
You've got a feverish baby and a bottle of children's ibuprofen, and the label has a cut-off you're not sure your baby has reached. The short answer: ibuprofen has two thresholds, not one, and your baby has to clear both.
The quick answer
- From 3 months old — and
- at least 5kg in weight.
- Both must be true. A 4-month-old who weighs under 5kg still shouldn't have it without medical advice.
- Under 3 months or under 5kg: ibuprofen only on a doctor's say-so.
Once your baby's old enough, our free dose-by-age calculator shows the right amount for each medicine.
The rule is "3 months AND 5kg"
This is the bit the label states but doesn't always explain. Over-the-counter children's ibuprofen (Nurofen for Children, Calprofen and the supermarket equivalents) is licensed for babies from 3 months of age and weighing at least 5kg. It's an "and", not an "or".
Most babies pass 5kg somewhere around 2–4 months, so for many the two thresholds line up. But babies who were premature or are simply on the smaller side can be 3 months old and still under 5kg — and for them, the weight is the one that counts. If in doubt, weigh first.
Why younger and smaller babies are excluded
Ibuprofen is a non-steroidal anti-inflammatory (NSAID). Unlike paracetamol, it works by reducing inflammation, and that mechanism puts a little more demand on the kidneys and the stomach lining. Very young or very small babies:
- have less mature kidney function;
- dehydrate faster when they're ill, which is exactly when NSAIDs are hardest on the kidneys;
- haven't been part of the testing that established safe over-the-counter use below those thresholds.
So the 3-month / 5kg line isn't arbitrary caution — it's the point below which ibuprofen simply hasn't been cleared for parents to give without a clinician involved.
What to give a younger baby instead
If your baby is too young or too small for ibuprofen, paracetamol (Calpol) is usually the option — but it has its own age rules:
- From 2 months, paracetamol can be given for fever after vaccinations, or for a baby who weighs over 4kg and was born after 37 weeks.
- Under 3 months, give paracetamol only on a doctor's advice.
- Any fever in a baby under 3 months should be assessed — ring your GP or NHS 111 rather than treating it at home.
For the amounts once your baby is old enough, see our Calpol dose by age chart.
When ibuprofen is ruled out even for an eligible baby
Past 3 months and 5kg, ibuprofen is still not right for every child. Avoid it (or check with a pharmacist or GP first) if your baby:
- has or has recently had chickenpox — ibuprofen is linked to skin complications;
- is dehydrated or not keeping fluids down;
- has asthma (some children react badly to NSAIDs);
- has a kidney, heart or stomach condition.
In those cases paracetamol is generally the safer choice. There's more in our guide to ibuprofen for children.
Giving it with food
One practical difference from Calpol: ibuprofen should be given with or after food, because on an empty stomach it's more likely to cause irritation. Paracetamol doesn't need food. If your baby has barely eaten, that can tip the decision toward Calpol.
Frequently asked questions
Can a baby have ibuprofen at 3 months?
Yes — provided they also weigh at least 5kg. If they're 3 months but under 5kg, don't give it without a doctor's advice.
Can newborns have ibuprofen?
No. Over-the-counter ibuprofen is not for babies under 3 months, and never for newborns, unless specifically prescribed.
My baby is 4 months but small for their age — can they have ibuprofen?
Check the weight. If they're under 5kg, ibuprofen isn't licensed for home use yet — use paracetamol if appropriate, and ask your pharmacist or GP.
Can I give ibuprofen and Calpol to a baby together?
Only once the baby meets the age and weight rules for each medicine. They can be combined or alternated in some situations — see Calpol and ibuprofen together — but for a young baby, check with a healthcare professional first.
How Dosey helps
Once your baby is old enough for both medicines, keeping their separate 4-hour and 6-8-hour clocks straight gets fiddly fast. Dosey tracks Calpol and ibuprofen independently and tells you exactly when each one is next available — no mental arithmetic at 3am.
This isn't medical advice. Dosey is a record-keeping tool, not a clinic. A fever in a baby under 3 months always needs a healthcare professional. The label on your bottle and your GP or pharmacist are the source of truth.