If you have a fever, the most important steps are to rest, stay hydrated, and monitor your temperature. Most fevers in adults under 103°F (39.4°C) aren’t dangerous and will resolve on their own as your immune system fights off an infection. Your job is to keep yourself comfortable, replace lost fluids, and watch for warning signs that something more serious is going on.
What Counts as a Fever
A normal body temperature hovers around 98.6°F (37°C), though it fluctuates throughout the day. Most healthcare providers define a fever as an oral temperature of 100.4°F (38°C) or higher. Temperatures between 99.5°F and 100.3°F are generally considered a low-grade fever, a sign your immune system has been mildly activated.
Keep in mind that how you take your temperature matters. Oral thermometers tend to read about 1.1°F lower than rectal thermometers, which are considered the most accurate measure of core body temperature. In one emergency department study, oral readings missed two-thirds of fevers that rectal readings caught. Ear (tympanic) thermometers can swing in either direction, reading up to 1.6°F too low or 2°F too high. If your oral reading is borderline and you feel genuinely unwell, the thermometer may be understating things.
Why Your Body Raises Its Temperature
Fever isn’t a malfunction. When your immune cells detect an invader, whether a virus, bacteria, or other pathogen, they release signaling molecules that travel to the temperature-control center in your brain. These signals trigger the production of a chemical messenger that essentially turns up the thermostat. Your brain then tells your body to conserve heat by narrowing blood vessels near the skin and to generate heat through shivering. That’s why you feel cold and shaky even though your temperature is climbing.
This elevated temperature makes it harder for many pathogens to reproduce and helps certain immune cells work more efficiently. In most cases, the fever itself is doing useful work.
How to Manage a Fever at Home
The basics are straightforward: fluids, rest, and staying cool.
- Drink more than usual. Fever increases fluid loss through sweating and faster breathing. Water is fine, but broth and diluted juice also help replace electrolytes. For infants under one year, use an oral rehydration solution like Pedialyte rather than water or juice.
- Rest seriously. Physical activity raises your body temperature further and diverts energy your immune system needs. Lying on the couch counts as doing something productive.
- Dress lightly. Wear a single layer of light clothing, keep the room cool, and sleep with just a sheet or light blanket. Bundling up traps heat and can push your temperature higher.
Over-the-counter fever reducers like acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) can bring your temperature down and ease body aches. You don’t have to take them for a low-grade fever if you’re reasonably comfortable, since the fever is part of your immune response. But if you’re miserable, unable to sleep, or your temperature is climbing above 102°F, they help. Follow the dosing instructions on the package and don’t exceed 4,000 milligrams of acetaminophen in 24 hours, as higher amounts can damage the liver. Avoid ibuprofen if you have a history of stomach ulcers, kidney disease, or heart problems. Don’t combine either medication with alcohol.
What Not to Do
Rubbing alcohol on the skin is an old home remedy that should stay in the past. While alcohol sponging can lower temperature slightly faster than tepid water in the first hour, it causes significantly more adverse effects, including skin irritation and, in rare cases, loss of consciousness from inhaling the fumes or absorbing alcohol through the skin. By the second hour, outcomes are the same regardless of method. There’s no benefit worth the risk.
Ice baths and ice packs applied directly to the skin are also a bad idea. They can cause shivering, which actually generates more internal heat and works against what you’re trying to accomplish. If you want external cooling, a lukewarm (not cold) washcloth on your forehead or a tepid sponge bath is safer and more comfortable.
Fever in Babies and Young Children
The rules are stricter and the thresholds are lower for young children. Any fever at all in a baby under 3 months old warrants an immediate call to your pediatrician, regardless of the temperature. The immune system at that age is too immature to reliably fight infections, and fever can signal something serious.
For babies 3 to 6 months old, call your doctor for any temperature above 100.4°F, or for a lower temperature if the baby seems unusually lethargic or irritable. Between 6 and 24 months, a fever above 100.4°F that lasts more than one day needs medical attention. For children over two, the threshold for concern rises to 104°F (40°C), though you should still call sooner if your child seems very unwell, refuses fluids, or is difficult to wake.
Never give aspirin to children or teenagers with a fever, as it’s linked to a rare but serious condition called Reye’s syndrome.
Warning Signs That Need Immediate Attention
Most fevers are caused by common viral infections and resolve within a few days. But certain symptoms alongside a fever point to conditions that need urgent evaluation:
- Stiff neck with pain when bending your head forward (a hallmark of meningitis)
- Mental confusion, altered speech, or strange behavior
- Seizures or convulsions
- A new rash, especially one that doesn’t fade when pressed
- Unusual sensitivity to bright light
- Persistent vomiting
- Difficulty breathing or chest pain
- Severe abdominal pain
- Pain when urinating
- Severe headache that doesn’t respond to medication
In adults, a fever above 103°F that isn’t coming down with medication is worth a call to your doctor. Any fever above 105.8°F (41°C) is a medical emergency. A fever that persists beyond three days, even at a moderate level, also deserves a professional evaluation, since it may indicate a bacterial infection that needs targeted treatment rather than just time.
Viral vs. Bacterial Fever
Most fevers come from viral infections: colds, flu, stomach bugs. These don’t respond to antibiotics and simply need time. Bacterial infections like strep throat, urinary tract infections, or pneumonia may produce similar symptoms but typically require antibiotics to clear.
The tricky part is that it’s genuinely difficult to tell the two apart based on symptoms alone. Even clinicians rely on testing rather than guesswork. Current infectious disease guidelines recommend using clinical scoring tools to assess whether a sore throat with fever is likely strep or viral before ordering a test, since most cases turn out to be viral and resolve without specific therapy. If your fever comes with a clearly localizing symptom, like burning with urination or a productive cough with colored mucus, that gives your doctor a useful starting point for deciding whether testing or antibiotics make sense.