For most adults with a fever, acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) are the two go-to options. Both effectively lower body temperature, and choosing between them comes down to your age, health history, and what else is going on in your body. A fever is generally defined as a temperature of 100.4°F (38°C) or higher, whether measured orally, rectally, or with an ear thermometer.
Before reaching for medication, it helps to know that a fever itself isn’t the enemy. It’s your immune system’s way of fighting infection. Treating it is about comfort, not curing the underlying illness. Here’s what works, what’s safe, and what to watch for.
Acetaminophen (Tylenol)
Acetaminophen is the most widely used fever reducer. It works well for both adults and children, and it’s gentle on the stomach compared to anti-inflammatory options. You can take it every four to six hours as needed.
The critical safety limit for adults is 4,000 milligrams in a 24-hour period, combining all sources. That last part matters: acetaminophen hides in dozens of over-the-counter products, including cold medicines, sleep aids, and combination pain relievers. If you’re taking any other medication, check the label for acetaminophen before adding more. Exceeding the daily limit can cause serious liver damage, and the risk increases significantly if you drink alcohol regularly.
For children, the dose is weight-based: 10 to 15 milligrams per kilogram of body weight, given every four to six hours. The maximum for children is 75 milligrams per kilogram per day, not to exceed the adult ceiling of 4,000 milligrams. Always use the measuring device that comes with the product rather than a kitchen spoon.
Ibuprofen (Advil, Motrin)
Ibuprofen reduces fever and also fights inflammation, which can be helpful if the fever comes with body aches, sore throat, or headache. The standard adult dose is 400 milligrams every six to eight hours as needed.
Ibuprofen is harder on the stomach than acetaminophen, so taking it with food helps. It’s not ideal if you have a history of stomach ulcers, kidney problems, or if you’re on blood thinners. For children, ibuprofen is safe from six months of age onward, dosed by weight. Do not give ibuprofen to a baby younger than six months unless directed by a pediatrician.
Research published in Pediatrics by the American Academy of Pediatrics found that ibuprofen tends to bring a fever down faster than acetaminophen in the first four hours, though by six hours the two perform similarly.
Alternating the Two Medications
If a single medication isn’t keeping the fever under control, alternating between acetaminophen and ibuprofen is a common strategy. The same AAP meta-analysis found that alternating or combining the two was significantly more effective than using either one alone. At the four-hour mark, children receiving alternating therapy were roughly 3.5 times more likely to be fever-free compared to those on acetaminophen alone. At six hours, the advantage held at about five times more likely.
The safety data was reassuring: no increase in side effects was found when the two were alternated at appropriate doses over the short term. The practical approach is to give one medication, then give the other three to four hours later, continuing to rotate. Writing down each dose and the time helps avoid accidentally doubling up on one.
What Not to Take
Never give aspirin to children or teenagers. Aspirin is linked to Reye’s syndrome, a rare but potentially life-threatening condition that causes swelling in the liver and brain, particularly when given during a viral illness like the flu or chickenpox. Aspirin can appear under other names on labels, including acetylsalicylic acid, acetylsalicylate, and salicylate. It also shows up in products you might not expect, like Alka-Seltzer. Always read the ingredients before giving any medication to a child.
The one exception: children with certain chronic conditions like Kawasaki disease may need aspirin as part of their treatment plan, but only under direct medical supervision.
Fever During Pregnancy
Acetaminophen is the safest choice for fever during pregnancy. The American College of Obstetricians and Gynecologists has affirmed its safety, noting that it is one of the few options available to pregnant patients and that untreated fever itself poses risks. Ibuprofen and other anti-inflammatory medications should generally be avoided during pregnancy, particularly in the third trimester, because they can affect fetal development and amniotic fluid levels.
Home Remedies That Help
Medication works best alongside basic comfort measures. Staying well-hydrated is the single most important non-drug step, since fever increases fluid loss through sweating and faster breathing. Water, broth, and electrolyte drinks all help. Rest lets your body direct energy toward fighting whatever is causing the fever.
Wearing light clothing and keeping the room at a comfortable temperature make a difference. Lukewarm sponging can provide some additional cooling, though the evidence for its effectiveness is mixed and it mainly helps with comfort. Never use alcohol-based sponges or ice baths to cool a fever. Alcohol can be absorbed through the skin and is toxic, while ice baths can cause shivering that actually raises your core temperature.
Fevers That Need Medical Attention
Most fevers resolve on their own or with basic treatment, but certain combinations of symptoms signal something more serious. Seek immediate medical help if a fever comes with a seizure, confusion, loss of consciousness, stiff neck, trouble breathing, severe pain, unusual swelling, painful urination, or foul-smelling discharge.
For infants, the rules are stricter. Any baby under three months old with a rectal temperature above 100.4°F needs to be seen by a doctor right away, even if the baby seems otherwise fine. Inconsolable crying, difficulty waking, a stiff neck, or purple spots on the skin in an infant with fever are all reasons to call immediately. For any child, a temperature reaching 105°F is a medical emergency.