For most fevers in adults, acetaminophen (Tylenol) or ibuprofen (Advil, Motrin) will bring your temperature down effectively. Both are available over the counter, work within about 30 to 60 minutes, and are safe for short-term use when taken as directed. Ibuprofen tends to be slightly more effective at reducing fever than acetaminophen, but either one is a reasonable first choice depending on your health history.
How Fever Reducers Work
When your body fights an infection, it produces a chemical messenger called prostaglandin E2 in the brain. This messenger resets your internal thermostat, housed in a region called the hypothalamus, to a higher temperature. That’s why you feel chilled even though your body is warming up: your brain has decided 101°F is the new normal, and it’s driving your body to get there.
Both acetaminophen and ibuprofen work by blocking the enzyme that produces prostaglandin E2. With less of that messenger circulating in the brain, your thermostat dials back down and your body starts cooling itself through sweating and increased blood flow to the skin.
Your Main Options
Acetaminophen (Tylenol)
Acetaminophen is the gentlest option on the stomach and is safe for most people, including pregnant women, for whom it remains the safest over-the-counter fever reducer available. The standard adult dose is 500 to 1,000 mg every four to six hours. Do not exceed 4,000 mg in 24 hours. For extra-strength formulations, the manufacturer recommends a lower ceiling of 3,000 mg per day. Because acetaminophen is processed through the liver, anyone with liver problems or who drinks alcohol regularly should use a lower dose or choose a different option.
Ibuprofen (Advil, Motrin)
Ibuprofen belongs to the NSAID class (nonsteroidal anti-inflammatory drugs) and reduces both fever and inflammation. The standard adult dose is 200 to 400 mg every six to eight hours, with a daily maximum of 1,200 mg for over-the-counter use. Because it’s processed through the kidneys and can irritate the stomach lining, ibuprofen is a poor choice if you have kidney disease, a history of stomach ulcers, or bleeding problems. Taking it with food helps reduce stomach irritation.
Naproxen (Aleve)
Naproxen is another NSAID that lasts longer per dose. Adults and children 12 and older can take one tablet (220 mg) every 8 to 12 hours, with a maximum of three tablets in 24 hours. For the first dose, you can take two tablets within the first hour. The same stomach and kidney warnings that apply to ibuprofen apply here, and the risk of stomach bleeding is higher if you’re over 60, take blood thinners, or drink three or more alcoholic beverages daily. People allergic to aspirin should avoid naproxen entirely.
Alternating Acetaminophen and Ibuprofen
If one medication alone isn’t keeping the fever down, you can alternate between acetaminophen and ibuprofen. The key is not to take both at the same time. Instead, take one, then wait four to six hours and take the other. You can continue rotating every three to four hours throughout the day. This approach works because the two drugs lower fever through slightly different pathways, and their dosing schedules overlap enough to maintain more consistent relief.
Stay within the daily maximums for each: no more than 4,000 mg of acetaminophen and 1,200 mg of ibuprofen in 24 hours. If you find yourself alternating for more than three days, it’s worth checking in with a healthcare provider.
Fever Reducers for Children
Children’s dosing is based on weight, not age, which is why liquid formulations come with a syringe or dosing cup. Acetaminophen can be given every four to six hours (up to five doses in 24 hours) to children 3 months and older. Ibuprofen can be given every six to eight hours (up to four doses in 24 hours) to children 6 months and older. For babies younger than those cutoffs, do not give fever medication without a doctor’s guidance.
One medication to avoid entirely in children and teenagers: aspirin. Using aspirin during a viral illness, particularly the flu or chickenpox, has been linked to Reye’s syndrome, a rare but serious condition that causes swelling in the liver and brain. This applies to anyone under 18.
Non-Drug Ways to Feel Better
Medication is only part of managing a fever. Your body loses fluids faster when your temperature is elevated, so staying hydrated matters more than usual. Water is fine, but broth and oral rehydration solutions (like Pedialyte or similar products) are better choices if you’re also vomiting or have diarrhea, because they replace lost minerals along with fluid.
Dress in light layers and keep the room comfortable rather than piling on blankets. A lukewarm (not cold) washcloth on the forehead can offer some relief. Cold baths or ice packs are counterproductive because they trigger shivering, which actually raises your core temperature further. Rest is the simplest and most effective complement to any fever reducer.
When a Fever Needs Medical Attention
A fever is defined as a body temperature of 100.4°F (38°C) or higher. Most fevers fall into the low-to-moderate range, between 100.4°F and 102.2°F, and resolve on their own within a few days. A temperature over 104°F (40°C) in an adult warrants a call to your doctor.
Regardless of the number on the thermometer, seek medical help right away if a fever comes with any of these symptoms:
- Seizure or loss of consciousness
- Confusion or difficulty thinking clearly
- Stiff neck
- Trouble breathing
- Severe pain anywhere in the body
- Swelling or inflammation in any body part
- Pain with urination or foul-smelling urine
For infants under 3 months, any fever of 100.4°F or higher is a reason to contact a pediatrician immediately, even if the baby seems otherwise fine. Young infants don’t show reliable warning signs the way older children and adults do, so the temperature alone is enough to act on.
Pregnancy Considerations
Acetaminophen remains the recommended choice during pregnancy. Both ibuprofen and aspirin carry documented risks to fetal development, particularly later in pregnancy. That said, the FDA has encouraged clinicians to minimize even acetaminophen use during pregnancy for routine low-grade fevers when possible. If you’re pregnant and your fever is 101°F or higher, the benefit of bringing the temperature down generally outweighs the risk of a short course of acetaminophen.