A fever is your body’s natural defense against infection, and most fevers resolve on their own with rest, fluids, and basic comfort measures. A temperature of 100.4°F (38°C) or higher, measured orally, rectally, or by ear, counts as a fever. In most cases, bringing it down is about making yourself more comfortable while your immune system does its job.
Why Your Body Runs a Fever
When your immune system detects an invader like a virus or bacteria, it triggers a chain reaction that raises your body’s internal thermostat. The part of your brain that controls temperature gets a chemical signal to set a new, higher target. Your body then works to reach that target by generating heat (think shivering and chills) and conserving it by narrowing blood vessels near your skin.
This isn’t a malfunction. Elevated body temperature stimulates nearly every component of your immune system, making your white blood cells more active and your body a less hospitable environment for pathogens. Artificially cooling yourself down with ice packs or cold water can actually blunt this immune response, which is why physical cooling methods are generally discouraged unless your temperature reaches dangerously high levels.
Step-by-Step Home Care
Stay Hydrated
Fever increases water loss through your skin. For every degree above 100.4°F, your body loses roughly 10% more fluid than normal. Water is fine. So are diluted juice, broth, oral rehydration solutions, and herbal tea. Avoid alcohol and large amounts of caffeine, both of which can dehydrate you further. If your urine is dark yellow or you’re urinating less than usual, you need to drink more.
Rest
Your body is diverting energy toward fighting infection. This is why you feel wiped out. Don’t push through it. Sleep as much as your body wants, and skip exercise until the fever breaks. Light, easy-to-digest foods are enough if you have any appetite at all.
Dress Lightly and Keep the Room Comfortable
Bundling up in heavy blankets feels instinctive when you have chills, but it can trap heat and push your temperature higher. Wear lightweight clothing and use a single light blanket. Keep the room at a comfortable temperature rather than cranking up the heat.
Use Fever-Reducing Medication When You Need Comfort
You don’t have to take medication for every fever. If you’re reasonably comfortable, letting the fever run its course is perfectly fine. But if you feel miserable, acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) can help.
- Acetaminophen: Take every 4 to 6 hours as needed, no more than 5 doses in 24 hours.
- Ibuprofen: Take every 6 to 8 hours as needed, no more than 4 doses in 24 hours.
Follow the dosing instructions on the package and don’t combine multiple products that contain the same active ingredient, which is a common cause of accidental overdose with acetaminophen in particular.
Skip the Sponge Bath
Tepid sponge baths are a popular home remedy, but research shows they don’t reduce fever any better than medication alone over a two-hour period. In a study of febrile children, those who received sponge baths had significantly higher discomfort scores with no meaningful temperature benefit. Save yourself the misery.
Fever in Babies and Children
Infants under 3 months old with a temperature of 100.4°F or higher need emergency medical attention immediately, regardless of how well they seem. Their immune systems are too immature to reliably fight serious infections, and a fever at that age can signal something that requires urgent treatment.
For older children, the same general principles apply: fluids, rest, and fever-reducing medication if they’re uncomfortable. Ibuprofen should not be given to babies under 6 months old. Acetaminophen should not be given to infants under 8 weeks old. Never give aspirin to children or teenagers, as it has been linked to Reye’s syndrome, a rare but potentially fatal condition that causes swelling in the liver and brain, particularly during viral illnesses like the flu or chickenpox.
When a Fever Becomes Dangerous
Most fevers in adults are harmless, even when they feel terrible. But certain situations call for immediate medical attention. Adults with a fever of 103°F (39.4°C) or higher will typically look and act noticeably sick, and that’s a reasonable threshold for calling your doctor.
Head to the emergency room if a fever comes with any of these symptoms:
- Stiff neck that resists movement (a warning sign for meningitis)
- Severe headache or sensitivity to light
- Confusion, altered speech, or difficulty waking up
- Seizures or convulsions
- Difficulty breathing
- Rash, especially one that looks like small bleeding spots under the skin
- Abdominal pain, nausea, or vomiting
At the extreme end, a body temperature above 106.7°F (41.5°C) is called hyperpyrexia and is a medical emergency. At that level, the heat itself starts damaging organs. The brain, heart, lungs, liver, and kidneys can all be affected, and without rapid cooling, the result can be permanent brain damage, organ failure, or death. This is rare with a typical infection and more commonly associated with heat stroke or certain drug reactions.
How Long a Fever Typically Lasts
Most fevers caused by common viral infections peak within the first day or two and resolve within three to five days. A fever that lasts longer than that, or one that goes away and comes back after a day or more of normal temperature, is worth a call to your doctor. The same goes for a low-grade fever that lingers for more than a week or two with no obvious cause, as it may point to an underlying condition that needs investigation.
Once the fever breaks, expect to feel drained for another day or two. Your body has been running at high intensity, and it needs time to recover even after your temperature returns to normal.