Most fevers in adults and children can be brought down at home with over-the-counter medication, fluids, and simple cooling techniques. A temperature of 100.4°F (38°C) or higher, measured orally or rectally, is considered a fever. Before you reach for medicine, though, it helps to understand that not every fever needs to be reduced, and the approach differs depending on age.
Why Your Body Raises Its Temperature
Fever isn’t a malfunction. When your immune system detects an infection, small blood vessels in the brain release a signaling molecule called prostaglandin E2. This molecule acts on a cluster of neurons in the hypothalamus, the part of the brain that works like a thermostat. The signal effectively resets your body’s target temperature higher, triggering shivering, blood vessel constriction, and that familiar sensation of feeling cold even though your skin is hot.
The elevated temperature serves a purpose: it activates additional waves of immune defense and makes the body a more hostile environment for many bacteria and viruses. Fever as an immune strategy is estimated to be over four million years old and appears across a wide range of species, from insects to mammals. This is why some physicians argue that a mild fever (under about 102°F) in an otherwise healthy person may be worth leaving alone, especially if you’re not particularly uncomfortable. The immune boost from a moderate fever can help resolve an infection faster.
That said, fever increases your metabolic rate, raises your heart rate, and accelerates fluid loss. For people who are already physically stressed, very young, or very old, those costs can outweigh the immune benefits. In those cases, bringing the temperature down is the right call.
Over-the-Counter Fever Reducers
The two most common options are acetaminophen (Tylenol) and ibuprofen (Advil, Motrin). Both work by interfering with the production of prostaglandin E2, the same molecule that tells your brain to raise its thermostat. They typically begin lowering a fever within 30 to 60 minutes.
For adults and anyone over 12, acetaminophen can be taken every four to six hours as needed, but the total should never exceed 4,000 milligrams (4 grams) in a 24-hour period. That ceiling is important because acetaminophen is processed by the liver, and exceeding it raises the risk of serious liver damage. Ibuprofen is generally taken every six to eight hours. Some combination products contain both, with a typical dose of 250 mg acetaminophen and 125 mg ibuprofen per tablet, taken every eight hours up to six tablets per day.
If one medication alone isn’t keeping the fever down, some people alternate between acetaminophen and ibuprofen. For example, taking acetaminophen, then ibuprofen three hours later, then acetaminophen three hours after that. This can provide more consistent relief, but keep careful track of doses and timing to avoid accidentally doubling up on either drug.
Fever Medicine for Children
Children’s dosing is based on weight, not age. If you don’t know your child’s current weight, age can serve as a rough guide, but weighing them first is more accurate. Liquid acetaminophen for children comes in a standard concentration of 160 mg per 5 mL. It can be given every four hours, with a maximum of five doses in 24 hours. Children under 2 should not receive acetaminophen without guidance from a pediatrician.
Extra-strength acetaminophen (500 mg tablets) is not appropriate for children under 12, and extended-release formulations (650 mg) should not be given to anyone under 18.
One critical rule: never give aspirin to children or teenagers. Aspirin use during viral illnesses like the flu or chickenpox is linked to Reye’s syndrome, a rare but potentially fatal condition that causes swelling in the liver and brain. The only exception is children on long-term aspirin therapy for specific conditions like Kawasaki disease, prescribed and monitored by a doctor.
Cooling Techniques That Actually Help
Medication is the most effective way to lower a fever, but physical cooling methods can provide additional comfort, especially while you’re waiting for a dose to kick in.
A lukewarm sponge bath is the best-studied non-drug approach. Use water between 90°F and 95°F (32–35°C), and sponge for 20 to 30 minutes. The key word is lukewarm. Cold water, ice baths, and rubbing alcohol are all counterproductive. They cool the skin too quickly, which triggers shivering. Shivering is your body’s way of generating heat, so it actually drives your core temperature back up and makes you more uncomfortable. If sponging causes shivering at any point, stop.
Other simple measures that help: remove extra layers of clothing and blankets, keep the room comfortably cool (not cold), and place a damp cloth on the forehead or back of the neck. These won’t dramatically lower a high fever on their own, but combined with medication, they can make a noticeable difference in comfort.
Fluids and Rest
Fever increases fluid loss through sweating and faster breathing. Even a moderate fever can lead to dehydration surprisingly quickly, especially in children. Drink water, diluted juice, or broth regularly, in small sips if needed. For babies under one year, an oral rehydration solution like Pedialyte is a better choice than plain water because it replaces both fluids and electrolytes in the right proportions. Pedialyte ice pops can work well for older infants and toddlers who resist drinking.
Sleep is equally important, and not just because you feel exhausted. During deep sleep, your metabolic rate drops to its lowest point, which frees up energy for your immune system to mount a stronger response. Your body actually restructures its sleep cycles during infection, spending more time in deep sleep and less in the dreaming stage (REM sleep). This shift appears to be a deliberate immune strategy rather than a side effect of feeling sick. So if a fever is making you drowsy, that’s your body telling you exactly what it needs. Don’t fight it.
When a Fever Needs Medical Attention
Any baby under 3 months old with a fever of 100.4°F or higher needs immediate medical evaluation, regardless of how the baby appears. At that age, a fever can signal a serious infection that progresses quickly.
For older children, contact a doctor if the fever lasts more than five days, or if the child shows signs of dehydration: no wet diapers for 8 to 10 hours, crying without tears, a dry mouth, or refusal to drink. A stiff neck, persistent headache, abdominal pain, trouble breathing, rash, or joint swelling also warrant a call. If your child’s behavior doesn’t improve after taking fever-reducing medicine, that’s another reason to seek care. Fever itself is less concerning than how the child acts between fevers.
For adults, a fever alone is rarely an emergency. But a fever combined with trouble breathing, chest pain, a severe headache, or a stiff neck needs prompt evaluation. The same applies to a fever after being in a hot car or extreme heat, particularly if there’s no sweating, repeated vomiting, or confusion, which are signs of heat-related illness rather than infection.