For most fevers, the best approach is a combination of rest, plenty of fluids, and an over-the-counter fever reducer like acetaminophen or ibuprofen if you’re uncomfortable. A fever itself isn’t an illness. It’s your body’s immune response, and in most cases it resolves on its own within a few days. The goal isn’t always to eliminate the fever entirely, but to keep yourself comfortable and hydrated while your body fights off whatever triggered it.
Why Your Body Runs a Fever
A fever starts in a small region of the brain that acts as your body’s thermostat. When you get an infection, your immune system releases signaling molecules that essentially reset that thermostat to a higher temperature. Your body then works to reach that new set point the same way it normally keeps you warm: blood vessels near the skin constrict to trap heat, your metabolism ramps up to generate more warmth, and in some cases you start shivering. That’s why you can feel freezing cold even though your temperature is climbing. The chills, the shaking, the urge to pile on blankets are all your body actively trying to heat itself up to that new target.
Acetaminophen vs. Ibuprofen
Both acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) effectively lower a fever, but they work differently. Ibuprofen reduces inflammation in addition to lowering temperature, while acetaminophen primarily targets pain and fever without anti-inflammatory effects. In head-to-head studies, ibuprofen has a slight edge: children given ibuprofen had temperatures about 0.4°C (roughly 0.7°F) lower within four hours compared to those given acetaminophen, and they were roughly twice as likely to be fever-free between four and 24 hours after a dose.
That said, both are effective and safe for most people when used as directed. Acetaminophen is gentler on the stomach, making it a better choice if you’re already dealing with nausea. Ibuprofen can irritate the stomach lining, so take it with food. The maximum safe dose of acetaminophen for adults is 4,000 milligrams in 24 hours, but many experts recommend staying below 3,000 milligrams to protect the liver, especially if you drink alcohol. For ibuprofen, adults should not exceed 1,200 milligrams per day when self-treating.
One important note for children: never give aspirin to anyone under 18 during a fever or viral illness. It’s linked to a rare but serious condition called Reye’s syndrome that affects the liver and brain. Stick with acetaminophen or ibuprofen for kids, and always dose by weight rather than age for the most accurate amount. For children under 2, check with a pediatrician before giving either medication.
Fluids Matter More Than You Think
A fever increases water loss through your skin and breathing. For every degree Celsius your temperature rises above normal, your body’s fluid loss through the skin increases by roughly 10%. At 102°F (38.9°C), that adds up quickly, especially if the fever lasts more than a day. Dehydration is one of the main reasons fevers become dangerous, particularly in young children and older adults.
Water is fine, but drinks that replace electrolytes (like oral rehydration solutions or diluted sports drinks) are better if you’re sweating heavily or not eating much. Warm broth serves double duty by providing fluids and a small amount of sodium. Avoid alcohol and large amounts of caffeine, both of which pull water out of your system. A good rule of thumb: if your urine is dark yellow or you’re urinating less frequently than normal, you need to drink more.
Rest and Sleep
Sleep is one of the most underrated fever treatments. Your immune system is significantly more active during sleep, and cutting rest short can slow recovery. People who consistently get less than seven hours of sleep per night are three times more likely to develop a cold compared to those sleeping eight hours or more. Studies on vaccinations show the same pattern: people who were sleep-deprived in the days before and after getting a flu shot produced fewer protective antibodies than those who slept normally.
During a fever, your metabolic rate is elevated and your body is burning through energy faster than usual. Resting reduces the competing demands on that energy, letting more of it go toward your immune response. This isn’t the time to push through a workout or a full workday. If your body is telling you to sleep, listen to it.
Do Lukewarm Baths Actually Help?
Tepid sponging and lukewarm baths are traditional fever remedies, but the evidence for them is surprisingly thin. A systematic review of studies comparing sponging plus fever-reducing medication against medication alone found no significant difference in temperature reduction after two hours. Some studies noted a slightly faster initial drop in temperature with sponging, but the effect disappeared quickly. More importantly, several studies reported that children experienced noticeable discomfort during sponging, likely from the jarring sensation of water that feels cool against feverish skin.
If a lukewarm bath feels soothing to you, there’s no harm in it. But avoid cold water or ice baths, which can trigger shivering and actually raise your core temperature as your body fights to warm itself back up. A cool washcloth on the forehead is a gentler option that many people find comforting without the downsides.
Other Comfort Measures
Dress in lightweight, breathable clothing. It’s tempting to bundle up when you have chills, but heavy blankets and layers trap heat and can push your temperature higher once the fever peaks. A single light blanket is usually enough. Keep the room at a comfortable temperature rather than cranking the heat.
Eat if you can, even small amounts. Your body needs fuel to mount an immune response. Simple foods like toast, crackers, soup, and fruit are easier to tolerate when your appetite is low. Don’t force large meals, but don’t skip eating entirely for days at a time either.
Temperatures That Need Medical Attention
A fever is generally defined as a temperature of 100.4°F (38°C) or higher. Most fevers in the 100 to 103°F range in otherwise healthy adults, while uncomfortable, are not dangerous. Seek medical care for an adult with a fever accompanied by trouble breathing, chest pain, or a severe headache with a stiff neck.
For infants under 3 months old, any fever at all warrants immediate medical attention, regardless of how the baby looks or acts. For older children, call a doctor if the fever lasts more than five days, if the child shows signs of dehydration (no wet diapers for 8 to 10 hours, no tears when crying, dry mouth), has a stiff neck, persistent vomiting or diarrhea, difficulty breathing, or a rash. A fever that briefly spikes and comes down with medication is generally less concerning than one that persists despite treatment and is accompanied by worsening symptoms.