Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) are the two main over-the-counter options for bringing down a fever in both adults and children. Both typically start working within 30 to 60 minutes and last four to six hours. Which one you reach for depends on your age, health history, and what else is going on in your body.
Acetaminophen vs. Ibuprofen
Acetaminophen and ibuprofen lower fever effectively, but they work differently. Acetaminophen acts on the brain’s temperature-regulation center. Ibuprofen does that too, but it also reduces inflammation throughout the body, which makes it a better choice when fever comes with swelling, sore throat, or muscle aches.
Acetaminophen tends to kick in slightly faster, around 30 to 45 minutes, while ibuprofen takes closer to 30 to 60 minutes. Both last about four to six hours per dose. If you need longer-lasting coverage, naproxen (Aleve) is another option that can work for up to seven hours, though it carries the same precautions as ibuprofen.
For most healthy adults with a straightforward fever, either medication works well. If one isn’t bringing your temperature down enough on its own, combination tablets containing both acetaminophen and ibuprofen are available over the counter. The standard combo tablet contains 250 mg of acetaminophen and 125 mg of ibuprofen, taken every eight hours as needed, up to six tablets per day.
Safe Dosing for Adults
The most important number to remember with acetaminophen is 4,000 mg (4 grams) in 24 hours. That’s the absolute ceiling for adults, and many doctors recommend staying below 3,000 mg if you drink alcohol or take it regularly. This limit includes all sources of acetaminophen, and it’s hidden in a surprising number of products: cold medicines, sleep aids, and prescription painkillers. Always check the label.
For ibuprofen, the typical over-the-counter dose is 200 to 400 mg every four to six hours, with a daily maximum of 1,200 mg unless directed otherwise by a doctor. Take it with food or water to protect your stomach.
Fever Medication for Children
Children’s liquid acetaminophen comes in a standard concentration of 160 mg per 5 mL. For kids under 12, you can give a dose every four hours as symptoms last, but no more than five doses in 24 hours. Children under 2 should not receive acetaminophen without a doctor’s guidance, and extra-strength (500 mg) products are off-limits for anyone under 12.
Ibuprofen can be used in children 6 months and older, following the weight-based instructions on the package. Dosing by weight is more accurate than dosing by age, so weigh your child if you can.
One medication that should never be given to children or teenagers for fever: aspirin. It’s linked to Reye’s syndrome, a rare but serious condition that can cause brain damage or death, particularly when a child has the flu or chickenpox. This applies to plain aspirin and any product that contains it. The only exception is children with specific chronic conditions like Kawasaki disease, where a doctor prescribes aspirin directly. For children under 6, stick to single-ingredient medicines rather than multi-symptom formulas.
Who Should Avoid Certain Fever Reducers
Ibuprofen and naproxen belong to a class of drugs called NSAIDs, and they aren’t safe for everyone. People with kidney disease, particularly those with reduced kidney function, should avoid NSAIDs entirely. The same goes for people with liver disease, heart failure, or high blood pressure, and those taking blood pressure medications like ACE inhibitors or diuretics. NSAIDs can worsen all of these conditions.
Acetaminophen is generally the safer choice for people with kidney or heart concerns, but it carries its own risk: liver damage. If you have liver disease, check with your doctor before taking it. Combining acetaminophen with alcohol significantly increases the risk of liver injury, even at normal doses.
Home Care That Actually Helps
Medication is only part of managing a fever. Dehydration is one of the biggest risks, especially with high or prolonged fevers, so drink water, broth, or juice steadily throughout the day. For babies under 1, an oral rehydration solution like Pedialyte replaces both fluids and electrolytes more effectively than water alone.
Rest matters more than people give it credit for. Physical activity raises your core temperature, which works against what your body and medication are trying to do. Dress in light clothing, keep your room cool, and sleep with just a sheet or light blanket. Skip the heavy comforters, even if you have chills. Bundling up traps heat and can push your temperature higher.
When a Fever Needs Medical Attention
Not every fever requires a doctor, but certain situations do. Any baby under 3 months old with a fever needs immediate medical care, regardless of how high the temperature is. For older children, a fever lasting more than five days warrants a call to your pediatrician.
Adults should seek care when a fever reaches 103°F (39.4°C) or higher, especially if it comes with trouble breathing, chest pain, a severe headache, or a stiff neck. At that temperature, most people look and feel noticeably sick. A persistent fever that doesn’t respond to medication at all, or one that keeps returning after the medicine wears off for several days, is also worth getting checked out.