Most fevers don’t need to be “cured” because they aren’t a disease. A fever is your body’s built-in defense against infection, and in most cases it resolves on its own within a few days. What you can do is manage the discomfort, stay hydrated, and know when a fever signals something serious. A temperature of 100.4°F (38°C) or higher, measured orally or rectally, is the standard threshold for a fever in both adults and children.
Why Your Body Runs a Fever
When your immune system detects a threat like a virus or bacteria, it releases signaling molecules that act on the temperature-control center deep in your brain. These signals raise your body’s internal thermostat to a new, higher set point. Your body then works to reach that new target: blood vessels constrict, you shiver, and you pile on blankets because you feel cold even though your temperature is climbing.
This higher temperature makes it harder for many pathogens to reproduce and helps your immune cells work more efficiently. That’s why mild to moderate fevers are generally best left alone unless they’re making you miserable. The goal of treatment isn’t to eliminate the fever entirely but to bring it down enough that you can rest, eat, and drink comfortably.
Fever-Reducing Medication for Adults
Acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) are the two main over-the-counter options. Both lower your body’s thermostat set point by blocking the chemical chain reaction that raises it. They work through slightly different pathways, so some people respond better to one than the other.
For acetaminophen, the critical safety limit is 4,000 milligrams (4 grams) in a 24-hour period. Going above that threshold risks serious liver damage, especially if you drink alcohol regularly. Be careful with combination cold and flu products, which often contain acetaminophen you might not realize you’re doubling up on. Ibuprofen should be taken with food to protect your stomach lining, and people with kidney problems or a history of stomach ulcers should use it cautiously.
You don’t need to alternate the two medications unless the fever is particularly stubborn and uncomfortable. If one alone isn’t providing relief after an hour, the other can be added since they work independently. But for most fevers, a single medication taken at the recommended dose is enough.
Home Strategies That Actually Help
Staying hydrated is the single most important thing you can do. Fever increases your metabolic rate, which means your body burns through fluids faster than usual. Fluid needs rise roughly 10% for every degree Celsius above 38°C. Water, broth, diluted juice, and oral rehydration solutions all work. If your urine is dark yellow, you’re falling behind.
Lukewarm sponge baths can bring a fever down quickly, dropping temperature by more than 1.5°C within 30 minutes in studies on children. The catch is that the effect is short-lived. Within two hours, most of the temperature reduction disappears. Medication, by contrast, works more gradually but holds the temperature down for longer. The best approach is to use sponging for quick comfort while waiting for medication to kick in. Never use cold water, ice baths, or rubbing alcohol, all of which can cause shivering (which actually raises your core temperature) or dangerous skin absorption.
Dress in light, breathable clothing and keep the room comfortably cool. Bundling up feels instinctive when you have chills, but once the fever peaks and you start sweating, extra layers trap heat and delay cooling. Rest matters too. Your immune system is running an energy-intensive operation, and sleep gives it the resources it needs.
Eating When You Don’t Feel Like It
The old advice to “starve a fever” is wrong. Fever raises your metabolism, meaning your body needs more calories, not fewer. You don’t need to force large meals, but small, frequent bites of easy-to-digest foods like toast, rice, bananas, or soup give your body fuel to fight the infection. Protein is especially useful because your immune system relies on it to build antibodies. If solid food feels impossible, calorie-containing liquids like smoothies or broth with noodles are a reasonable substitute for a day or two.
Fever in Children: Different Rules Apply
Children’s fevers follow stricter guidelines based on age. For babies under 3 months, any rectal temperature of 100.4°F (38°C) or higher warrants an immediate call to a doctor, even if the baby seems fine. Their immune systems are too immature to reliably fight certain infections on their own. For children 3 to 6 months old, a temperature up to 101°F (38.3°C) is less urgent unless the child seems unusually irritable, limp, or hard to wake. Above that number, call your pediatrician. For children 6 to 24 months, a temperature above 101°F that persists beyond a full day needs medical attention.
Acetaminophen and ibuprofen are both safe for children when dosed correctly by weight, not age. Ibuprofen should not be used in babies under 6 months. One medication that is never appropriate for children or teenagers with a fever: aspirin. Aspirin given during a viral illness is linked to Reye’s syndrome, a rare but life-threatening condition that causes swelling in the liver and brain. This risk is highest with flu and chickenpox. Check labels carefully, because aspirin hides in products like Alka-Seltzer and may be listed as acetylsalicylic acid or salicylate.
When a Fever Needs Emergency Care
Most fevers break within three days. A fever that lingers beyond that, or one that climbs above 103°F (39.4°C) in an adult without responding to medication, deserves a doctor’s evaluation. But certain symptoms alongside a fever point to potentially dangerous conditions that need immediate attention:
- Stiff neck with pain when bending the head forward, which can signal meningitis
- Confusion, altered speech, or strange behavior
- Seizures or convulsions, especially in children (call 911 if a seizure lasts more than five minutes)
- A new rash, particularly one that doesn’t blanch when pressed
- Unusual sensitivity to bright light
- Difficulty breathing or chest pain
- Persistent vomiting that prevents you from keeping fluids down
- Pain when urinating, which may indicate a kidney infection
In children, watch specifically for poor eye contact, extreme listlessness, or a fever that developed after being left in a hot car. Heat-related fevers work differently from infection-related fevers and require emergency treatment.
How Long a Typical Fever Lasts
Viral infections, the most common cause of fever, typically produce fevers lasting two to three days. Some viruses like the flu can push that to five days. Bacterial infections may cause fevers that don’t improve without antibiotics. If your fever follows a clear pattern of getting better, then worse, then better again, that “double hump” can sometimes indicate a secondary bacterial infection developing on top of an initial viral one.
A low-grade fever (below 101°F) that persists for more than two weeks without an obvious cause falls into a different category. This pattern, sometimes called a fever of unknown origin, can be related to autoimmune conditions, certain medications, or less common infections that need targeted testing to identify.