When you have a fever, the most effective things you can do are rest, drink plenty of fluids, and take an over-the-counter fever reducer if you’re uncomfortable. Most fevers resolve on their own within a few days and are actually a sign your immune system is fighting an infection. A temperature of 100.4°F (38°C) or higher, measured rectally or with an ear thermometer, is considered a fever. Orally, the threshold is 100°F (37.8°C).
Why Your Body Raises Its Temperature
A fever isn’t a malfunction. It’s a deliberate response orchestrated by a part of your brain that acts as your internal thermostat. When your immune system detects an infection, it releases chemical signals that reach this brain region and essentially turn up the dial. Your brain then triggers a cascade of responses: your blood vessels near the skin constrict to trap heat, your muscles may start shivering to generate warmth, and your heart rate increases. This is why you can feel freezing cold even though your body temperature is elevated.
The higher temperature makes it harder for many viruses and bacteria to reproduce, and it speeds up certain immune functions. So while a fever feels miserable, it’s generally working in your favor.
Step-by-Step Home Care
Stay Hydrated
Fever increases fluid loss, and dehydration can creep up quickly, especially if you’re also sweating, vomiting, or have diarrhea. Water is fine, but juices and broth are also good options because they provide some electrolytes and calories when you may not feel like eating. For infants under one year, use an oral rehydration solution like Pedialyte, which has a specific balance of water and salts designed for small bodies. Sip consistently throughout the day rather than trying to drink large amounts at once.
Use Fever-Reducing Medication
Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) both lower fever effectively. You don’t have to take them if your fever is mild and you’re comfortable, but they help a lot when body aches, chills, or headaches are making you miserable. One important safety limit: never exceed 4,000 milligrams of acetaminophen in 24 hours, as higher amounts can cause serious liver damage. Be careful with combination products like cold medicines, which often contain acetaminophen you might not realize you’re doubling up on.
Never give aspirin to children or teenagers. It’s linked to a rare but serious condition called Reye’s syndrome, which can cause brain and liver damage.
Dress Lightly and Manage Blankets
Your instinct when you’re shivering may be to pile on blankets. It’s fine to use a light blanket if you’re feeling cold, but don’t overdo it. Too many layers can trap heat and push your body temperature even higher, increasing your risk of dehydration. Once the chills pass and you start feeling warm, peel layers off to let your body release heat naturally. Lightweight, breathable clothing works best.
Try a Lukewarm Sponge Bath
If your fever is high and you want additional relief beyond medication, a sponge bath with lukewarm water (around 90°F to 95°F) can help bring your temperature down. Do not use cold water, ice, or rubbing alcohol. These cool the body too rapidly, which triggers intense shivering. Shivering actually generates more heat and can push your temperature back up. If you or your child starts shivering during a sponge bath, stop immediately.
Rest
Your body is diverting significant energy toward fighting infection. Physical activity raises your core temperature further and delays recovery. Sleep as much as you can, and avoid exercise or strenuous activity until your fever has been gone for at least 24 hours.
How Long a Fever Typically Lasts
Most fevers from common viral infections (colds, flu, stomach bugs) last two to three days. Some can stretch to five days depending on the illness. For children, contact a doctor if a fever lasts longer than three days. For infants between 7 and 24 months old, a rectal temperature above 102°F (38.9°C) that persists beyond one day warrants a call, even if no other symptoms are present.
Fever in Babies Under 3 Months
Any fever in a baby younger than 3 months old requires an immediate call to your pediatrician, regardless of how high the temperature is. Newborns and very young infants have immature immune systems, and a fever can be the only sign of a serious bacterial infection. Don’t give fever-reducing medication to a baby this young without medical guidance, and don’t wait to see if the fever resolves on its own.
Signs That Need Immediate Medical Attention
Most fevers are harmless, but certain symptoms alongside a fever signal something more serious. Call your doctor or go to an emergency room if you experience any of the following with a fever:
- Seizure or loss of consciousness
- Confusion or difficulty staying alert
- Stiff neck, which can indicate meningitis
- Trouble breathing
- Severe pain anywhere in the body
- Swelling or inflammation in any area
- Painful urination or foul-smelling urine
A temperature above 104°F (40°C) in an adult also warrants a call to your doctor, even if you otherwise feel okay. At that level, the risks of the fever itself begin to outweigh the benefits of the immune response, and medical evaluation can rule out serious underlying causes.
Do You Always Need to “Break” a Fever?
Not necessarily. A low-grade fever (under about 102°F in adults) that isn’t causing significant discomfort can be left alone. Your immune system benefits from the elevated temperature, and forcing it down with medication doesn’t shorten the illness. The main reasons to treat a fever are comfort and preventing dehydration. If you’re able to rest, drink fluids, and tolerate the symptoms, it’s perfectly reasonable to let a mild fever run its course. Treat the fever when it’s making you too uncomfortable to sleep, eat, or stay hydrated.