GUIDE
Acetaminophen from birth, ibuprofen from 6 months — and always dose by weight, not age.
Both are safe and effective fever reducers when used correctly. The key differences are age eligibility, timing intervals, and how they work. This guide covers what you need to know to use them safely — including what to avoid and when to call your pediatrician for exact dosing.
When your baby has a fever, you have two over-the-counter medication options: acetaminophen (brand name Tylenol) and ibuprofen (brand names Motrin and Advil). Both are safe and effective when used correctly. Both reduce fever and help with pain. But they are different medications with different rules, and mixing up those rules is one of the most common — and most preventable — medication errors in pediatrics.
This guide covers what you need to know to use each one safely. What it does not include is specific dosing amounts — those depend on your baby's exact weight and the concentration of the product you have, and your pediatrician or pharmacist is the right person to provide them. What we can give you is the framework for understanding when to use which medication, how they differ, and the mistakes to avoid.
It is 11 PM and 8-month-old Lily has a temperature of 102.8F. Her parents gave her acetaminophen at 7 PM, and the fever came down to 100.5F — but now it is climbing back up. They are wondering: Can we give more Tylenol? Should we try Motrin instead? Can we give both?
Here is the framework. The acetaminophen was given 4 hours ago, so technically they could give another dose (it is safe every 4-6 hours). Alternatively, since Lily is over 6 months, they could give a dose of ibuprofen now instead, which would last longer through the night (6-8 hours). What they should NOT do is give both at the same time without their pediatrician's guidance.
They decided to call their pediatrician's after-hours line. The nurse suggested a dose of ibuprofen now, since it would provide longer coverage overnight, and recommended calling back in the morning if the fever was still present. They logged the dose time in their tracking app so they would know exactly when the next dose could safely be given.
This is the kind of clear thinking these medications require. Both are safe. Both work. But the timing, the age of the baby, and the specific situation all matter.
| Feature | Acetaminophen (Tylenol) | Ibuprofen (Motrin/Advil) |
|---|---|---|
| Generic name | Acetaminophen | Ibuprofen |
| Brand names | Tylenol, FeverAll (suppository), store brands | Motrin, Advil, store brands |
| Minimum age | Birth (with pediatrician guidance for dosing in newborns) | 6 months — do NOT give before 6 months |
| Dosing interval | Every 4-6 hours as needed | Every 6-8 hours as needed |
| How it works | Reduces fever and pain signals in the brain; does NOT reduce inflammation | Reduces fever, pain, AND inflammation (NSAID) |
| Time to take effect | 30-60 minutes | 30-60 minutes |
| Duration of effect | 4-6 hours | 6-8 hours (generally longer-lasting) |
| How to dose | By weight — ask your pediatrician or pharmacist | By weight — ask your pediatrician or pharmacist |
| Available forms | Liquid drops, liquid suspension, chewables, suppositories | Liquid drops, liquid suspension, chewables |
| Give with food? | Can be given with or without food | Best given with food or milk to reduce stomach irritation |
| Key caution | Overdose can cause serious liver damage; never exceed maximum daily doses | Can irritate the stomach; avoid in dehydrated babies or those with kidney concerns |
Choosing between acetaminophen and ibuprofen is usually straightforward, but there are situations where one is clearly better than the other.
The most important rule is the age cutoff. Ibuprofen should not be given to babies under 6 months old. Period. Before 6 months, a baby's kidneys are not mature enough to safely metabolize ibuprofen. If your baby is under 6 months and has a fever, acetaminophen is your only option. (And remember — any fever of 100.4F or higher in a baby under 3 months needs immediate medical evaluation. See our ER fever guide for the full age-based decision framework.)
For babies 6 months and older, both medications are safe, and your choice may come down to practical factors. Ibuprofen tends to last longer — 6 to 8 hours versus 4 to 6 for acetaminophen — which makes it useful for overnight fever management when you want longer coverage between doses. Ibuprofen also has anti-inflammatory properties that acetaminophen lacks, which can give it a slight edge for conditions involving swelling, such as ear infections or teething.
However, ibuprofen should be avoided if your baby is dehydrated or vomiting significantly. Because ibuprofen is processed through the kidneys and can reduce blood flow to them, it is not the right choice when a baby's fluid status is compromised. Acetaminophen, which is processed through the liver, is safer in that scenario.
If your baby is vomiting and cannot keep oral medication down, acetaminophen suppositories (brand name FeverAll) are available over the counter and bypass the stomach entirely. There is no suppository form of ibuprofen. Discuss this option with your pediatrician.
| Scenario | Recommended Medication | Why |
|---|---|---|
| Baby under 6 months with a fever | Acetaminophen (Tylenol) only | Ibuprofen is not safe before 6 months. Acetaminophen is the only option for this age group. |
| Baby 6+ months with a fever | Either acetaminophen or ibuprofen | Both are safe and effective. Ibuprofen tends to last longer (6-8 hours vs. 4-6), which can be helpful for overnight fevers. |
| Fever with teething pain | Either; ibuprofen may have a slight edge | Ibuprofen reduces inflammation in addition to pain, which may help with the gum swelling of teething. Only if baby is 6 months or older. |
| Fever with ear pain | Either; ibuprofen may have a slight edge | The anti-inflammatory properties of ibuprofen can help with ear infection pain and swelling. |
| Baby is vomiting | Acetaminophen suppository (FeverAll) | If baby cannot keep oral medication down, a rectal suppository bypasses the stomach entirely. Discuss with your pediatrician. |
| Baby seems dehydrated | Acetaminophen — avoid ibuprofen | Ibuprofen can affect kidney function, especially when a baby is dehydrated. Use acetaminophen until hydration improves. |
| Fever not responding to one medication alone | Call your pediatrician | They may suggest alternating the two medications, but get specific timing instructions rather than attempting this on your own. |
| Post-vaccination fever in a baby under 6 months | Acetaminophen | The only safe option for this age group. Some pediatricians suggest a dose before or after vaccines for comfort. |
When you are alternating medications or giving doses through the night, it is shockingly easy to forget what you gave and when. Log every dose in tinylog with the medication name and exact time. At 3 AM when the fever spikes again, you will know exactly what was given last and when the next safe dose can be given — no guessing, no mental math.
Here is what this guide deliberately does NOT include: specific milligram-per-kilogram dosing charts. And here is why.
The correct dose for your baby depends on their exact weight, and it also depends on the specific product concentration you are using. Infant drops and children's suspension are different concentrations. Store-brand products may differ from name-brand products. The packaging has changed over the years, and the concentration of infant acetaminophen drops was actually reformulated in 2011 to reduce confusion.
Rather than risk anyone using an outdated chart, the wrong concentration, or rounding in the wrong direction, the safe move is this: call your pediatrician or pharmacist for the exact dose for your baby's current weight, and confirm which product concentration you have.
Your pediatrician's office will give you this information over the phone — you do not need an appointment. Many offices proactively provide dosing sheets at well-child visits. Keep this sheet somewhere accessible (take a photo and save it to your phone). Update it at each well-check as your baby's weight changes.
What we can tell you is the general dosing rules:
Acetaminophen: Dosed by weight. Can be given every 4 to 6 hours as needed. Do not exceed 5 doses in 24 hours. Safe from birth with proper dosing.
Ibuprofen: Dosed by weight. Can be given every 6 to 8 hours as needed. Do not exceed 4 doses in 24 hours. Only for babies 6 months and older.
You will inevitably hear about alternating acetaminophen and ibuprofen — giving one, then the other a few hours later, going back and forth. This practice is extremely common. Many pediatricians recommend it for stubborn fevers. But it is worth understanding the nuances.
Alternating means giving acetaminophen, then 3 hours later giving ibuprofen, then 3 hours later giving acetaminophen again, and so on. Each individual medication is still being given within its own safe interval (every 4-6 hours for acetaminophen, every 6-8 hours for ibuprofen), but you are staggering them so the baby always has some fever-reducing coverage.
For a baby with a high fever that does not come down adequately with one medication alone, alternating provides more consistent fever reduction without exceeding the maximum dose of either drug. Some studies show slightly better fever control with alternating compared to a single agent.
The AAP notes that alternating two medications with different dosing intervals significantly increases the risk of dosing errors — giving too much of one, giving them too close together, or losing track of which one was given last. In sleep-deprived, stressed parents at 3 AM, this is a real concern, not a theoretical one.
Only alternate medications if your pediatrician specifically tells you to. If they do, write down every dose with the medication name and the exact time. Better yet, log it in a tracking app so you have an unambiguous record. Alternating from memory is where errors happen.
Most of these errors are honest mistakes made by exhausted parents. The single best prevention is logging every dose with the medication name, amount, and time.
While acetaminophen is technically safe from birth, dosing for very young or very small babies is tricky. The standard dosing charts on consumer packaging start at a minimum weight that may not cover your newborn. Always call your pediatrician for the exact dose for a baby under 3 months or under 12 pounds. Do not guess.
Acetaminophen shows up in more products than you might expect — cold medicines, cough syrups, some combination products. If you give Tylenol and then a cold remedy that also contains acetaminophen, you have double-dosed. Always read the active ingredients on every medication you give your baby. If in doubt, call your pharmacist.
Always use the measuring syringe that comes in the medication box. Kitchen teaspoons and tablespoons are not standardized and can lead to significant dosing errors. If you have lost the syringe, your pharmacist can give you a new one. Do not eyeball it.
The goal is not to get the temperature back to 98.6F. It is to bring the fever down enough that your baby can rest, eat, and drink. If the temperature drops from 103F to 101F after medication and your baby seems more comfortable, that is a success — even though the fever is not 'gone.' Do not re-dose early because the number is still elevated.
This is worth repeating in its own section. Aspirin and products containing salicylates (including bismuth subsalicylate, found in Pepto-Bismol) should never be given to anyone under 18. They are linked to Reye's syndrome — a rare but potentially fatal condition that causes sudden swelling in the liver and brain. There is no safe dose of aspirin for children.
If you have given fever-reducing medication at the correct dose and the fever is not budging at all after 60 to 90 minutes, or if your baby's behavior is concerning regardless of the temperature, it is time to call your pediatrician.
Some fevers simply do not respond fully to medication — the temperature may drop a degree or two but not normalize, and that is actually fine. The goal is comfort, not a specific number. But a fever that shows zero response to medication, or a baby who remains very unwell even after the fever comes down, deserves professional evaluation.
If your baby has a very high fever (104F or above) that is not responding to medication and the baby appears very unwell, consider a trip to the ER. See our ER fever guide for the complete decision framework.
And if your baby has a seizure during a fever — while frightening — it is usually a febrile seizure and is not caused by the medication or the lack of it. See our febrile seizures guide for what to do.
This guide is for informational purposes only and is NOT a substitute for professional medical advice. When in doubt, always call your pediatrician. If your baby is under 3 months with a fever, having difficulty breathing, showing signs of dehydration, or seems seriously unwell, seek immediate medical attention.
