Most fevers don’t need to be “cured” because they aren’t the illness itself. A fever is your immune system’s response to an infection, and in most cases it resolves on its own within a few days. What you can do is manage your comfort, stay hydrated, and use over-the-counter medications strategically to bring your temperature down when it’s making you miserable. A reading of 100.4°F (38°C) or higher, taken orally or rectally, is generally considered a fever.
Why Your Body Runs a Fever
Your brain’s thermostat, located in the hypothalamus, normally keeps your body close to 98.6°F. When you get an infection, your immune system releases signaling molecules that essentially turn up the thermostat’s set point. Your body then works to reach that new, higher temperature: blood vessels near the skin constrict to trap heat, your metabolism ramps up, and you may start shivering. That’s why you feel cold and reach for blankets even though your body is actually getting hotter.
This process isn’t random. The higher temperature makes it harder for viruses and bacteria to thrive, and your white blood cells become more active and respond faster at elevated temperatures. Your body is essentially making itself a hostile environment for whatever is causing the infection. This is why mild to moderate fevers often don’t need aggressive treatment. If you’re uncomfortable, treat the discomfort. If you’re tolerating it fine, the fever is doing useful work.
Fever-Reducing Medications
The two main over-the-counter options for adults are acetaminophen (Tylenol) and ibuprofen (Advil, Motrin). Both lower your temperature effectively, but they work through different mechanisms and have different risks. Ibuprofen reduces inflammation and fever together, so it can be especially helpful when body aches accompany the fever. Acetaminophen targets fever and pain without the anti-inflammatory effect but is gentler on the stomach.
For adults, a typical dose of ibuprofen is 400 mg (two standard pills) taken with food. Acetaminophen is commonly taken as 1,000 mg (two 500 mg pills). The key safety limits: no more than 4,000 mg of acetaminophen in 24 hours, and no more than 3,200 mg of ibuprofen. Exceeding the acetaminophen limit, especially over several days, can cause serious liver damage. Ibuprofen at high doses or over long periods can cause stomach bleeding, sometimes without warning. Drinking alcohol while taking either medication increases these risks.
Alternating the Two Medications
If a single medication isn’t keeping your fever or discomfort under control, you can alternate between acetaminophen and ibuprofen every three hours. A schedule might look like ibuprofen at 6 a.m., acetaminophen at 9 a.m., ibuprofen again at noon, and so on. This approach tends to keep more consistent fever relief throughout the day compared to using just one medication.
There’s one important caveat. While alternating appears more effective at keeping fevers down, the long-term safety data isn’t as solid as you might expect. The American Academy of Pediatrics notes that dual regimens are more complicated and increase the risk of accidental overdosing, since the two drugs have different timing intervals. Starting with a single medication and seeing if it’s enough is a reasonable first step.
Hydration Matters More Than You Think
A fever significantly increases how much water your body loses through the skin. For every degree Celsius above 38°C (100.4°F), your body’s water loss through the skin increases by roughly 10%. At higher fevers with rapid breathing, total fluid needs can jump by 15% or more compared to normal. This is why dehydration sneaks up on people with fevers, especially if nausea or a sore throat makes drinking unappealing.
Water is fine for most adults. If you’ve been sweating heavily or haven’t eaten much, an electrolyte drink can help replace lost sodium and potassium. Small, frequent sips work better than trying to gulp large amounts, particularly if your stomach is unsettled. Signs you’re falling behind on fluids include dark urine, dry mouth, dizziness when standing, and in children, fewer wet diapers or crying without tears.
Other Comfort Measures
Rest is straightforward but genuinely important. Your body is burning extra energy to maintain that higher temperature and fight the infection simultaneously. Pushing through a fever to go to work or exercise diverts resources your immune system needs.
Keep your environment comfortable but don’t pile on heavy blankets once the initial chills pass. Lightweight clothing and a normal room temperature let your body release excess heat. A lukewarm (not cold) washcloth on the forehead or a lukewarm bath can help you feel better. Avoid ice baths or very cold water, which can trigger shivering and actually drive your temperature higher as your body fights to warm back up.
Getting an Accurate Temperature Reading
The type of thermometer you use affects accuracy. Oral thermometers are the most practical for adults and give reliable readings. Forehead (temporal) thermometers are convenient but can be thrown off by sweat, direct sunlight, cold air, or holding the device too far from the skin. Ear thermometers can be inaccurate if earwax is present or the ear canal is shaped in a way that affects the reading.
Readings from different body sites don’t convert neatly. There’s no reliable formula for adding or subtracting a degree to make an armpit reading match an oral one. If you need precision, oral or rectal readings are your best bet. An armpit temperature of 99°F or higher is considered a fever, but the threshold for oral and rectal readings is 100.4°F.
Fevers in Babies and Children
Any fever in a baby under 3 months old requires immediate medical attention, regardless of how high the temperature is. Their immune systems are immature, and fever at that age can signal serious infections that progress quickly.
For older children, the fever itself is less important than how the child is acting. A child with a 102°F fever who is drinking fluids and playing is generally less concerning than a child with a 100.5°F fever who is limp, inconsolable, or refusing to drink. Watch for signs of dehydration (no wet diapers for 8 to 10 hours, dry mouth, no tears when crying), a stiff neck, rash, joint swelling, or behavior that doesn’t improve after fever-reducing medication. A fever lasting more than five days also warrants a call to the pediatrician.
Red Flags That Need Urgent Attention
Most fevers are caused by common viral infections and pass within a few days. But certain symptoms alongside a fever point to something more serious. Seek emergency care if a fever comes with a stiff neck and severe headache (possible meningitis), confusion or difficulty staying awake, seizures, repeated vomiting or diarrhea that prevents keeping fluids down, or a new rash that doesn’t fade when you press on it.
A fever that develops after being in a hot car or during extreme heat exposure, especially without sweating, may indicate heatstroke rather than infection. This is a medical emergency that requires immediate cooling and professional treatment. For adults, a fever above 103°F that doesn’t respond to medication, or any fever that persists beyond three days without an obvious cause like a cold, is worth a call to your doctor.