A fever is your body’s way of fighting infection, and most of the time the best thing you can do is stay comfortable and let it run its course. But certain common reactions, from bundling up in blankets to reaching for the wrong medication, can actually make things worse or create new problems. Here’s what to avoid.
Don’t Try to “Sweat It Out”
Piling on heavy blankets or wearing thick layers when you have a fever feels instinctive, especially when you’re shivering. But overdressing traps heat and can push your temperature higher. Your body is already generating extra warmth to fight the infection; adding insulation works against the cooling mechanisms your body needs. Wear lightweight, breathable clothing and use a single sheet or light blanket. If you’re shivering, a slightly warmer layer is fine temporarily, but strip it off once the chills pass.
Don’t Use Rubbing Alcohol on the Skin
This old home remedy is genuinely dangerous. Rubbing alcohol (isopropyl alcohol) evaporates quickly, which creates a brief cooling sensation, but that effect lasts only a minute or two. The real problem is what happens next: the alcohol absorbs through the skin and enters the bloodstream. In children, whose smaller bodies are especially susceptible, this can cause isopropyl alcohol poisoning, seizures, irregular heartbeat, coma, and even death. The Cleveland Clinic warns that the potential side effects are so severe that rubbing alcohol should never be applied to the skin to lower a temperature. This applies to adults too, though the risk is highest in kids.
If you want external cooling, a lukewarm (not cold) washcloth on the forehead or a lukewarm bath is a safer option. Avoid ice baths or very cold water, which can cause shivering and paradoxically raise your core temperature as your body fights to warm itself back up.
Don’t Panic Over a Low-Grade Fever
A temperature of 99 to 100.4°F in an adult is a low-grade fever and rarely needs aggressive treatment. Fever itself isn’t the enemy. It’s a sign that your immune system is actively working. Many people immediately try to bring any fever down to a perfectly normal reading, but a mild fever doesn’t need to be eliminated. Focus on how you feel rather than the number on the thermometer. If you’re reasonably comfortable, you can let a low-grade fever do its job without medication.
That said, certain thresholds do matter. For adults, a fever of 103°F or higher paired with symptoms like confusion, chest pain, difficulty breathing, or a stiff neck warrants immediate medical attention. For children, 100.4°F in an infant under three months old is a call-the-doctor situation. A fever of 105°F or higher in any child is a medical emergency.
Don’t Give Aspirin to Children or Teenagers
Aspirin has been linked to Reye’s syndrome, a rare but potentially fatal condition that causes swelling in the liver and brain. The risk is specifically tied to aspirin use during viral illnesses like the flu or chickenpox. The Mayo Clinic is clear: do not give aspirin to anyone under 19 during a fever. This includes products that contain aspirin as a hidden ingredient, like Alka-Seltzer. Aspirin can also appear on labels under other names, including acetylsalicylic acid, acetylsalicylate, salicylic acid, and salicylate. Acetaminophen and ibuprofen (in age-appropriate formulations) are safer alternatives for children.
Don’t Overmedicate or Mix Fever Reducers Carelessly
Taking too much of a fever reducer, or dosing too frequently, is one of the most common mistakes. Acetaminophen in excess can damage the liver. Taking doses closer together than the label directs doesn’t make the medicine work better; it just increases your risk of harm.
Alternating between acetaminophen and ibuprofen is a widespread practice, but it hasn’t been well studied for safety or effectiveness. Researchers have raised concerns that combining the two may increase the risk of kidney damage, because ibuprofen reduces a protective compound in the kidneys at the same time acetaminophen concentrations there are elevated. If you’re going to use a fever reducer, stick to one at a time and follow the dosing instructions on the package carefully. Using a single medication at the correct dose is the safer approach.
Don’t Wake a Sleeping Person for Fever Medicine
Sleep is one of the most powerful things your body can do while fighting an infection. If a child (or adult) with a fever has fallen asleep, let them rest. Seattle Children’s Hospital specifically advises against waking a sleeping child to give fever medicine. The rest they’re getting is more valuable than shaving off a degree of temperature. If they wake up on their own and seem uncomfortable, that’s the time to offer medication and fluids.
Don’t Skip Fluids
Fever increases your body’s metabolic rate and causes you to lose water faster than normal through sweat and faster breathing. Dehydration can set in quickly, especially in children and older adults, and it makes you feel significantly worse. Many people focus entirely on medication and forget that staying hydrated is just as important.
Water is the best choice. Electrolyte solutions work well too, particularly if you’ve been sweating heavily or can’t eat much. Avoid sugary drinks and alcohol, both of which can worsen dehydration. You don’t need to calculate an exact amount. Just aim to drink noticeably more than you normally would, taking frequent small sips throughout the day even if you’re not thirsty. If your urine is dark yellow, you need more fluids.
Don’t Exercise or Push Through It
Working out with a fever puts real strain on your heart and body. Your heart rate and metabolic demands are already elevated from the fever itself, and adding exercise on top of that creates a compounding effect. Animal research has shown that forced exercise during viral illness dramatically increases the risk of heart muscle inflammation (myocarditis) and, in extreme cases, sudden cardiac death. In one well-known study, mice forced to exercise while fighting a viral infection had a 50% death rate from heart damage, with the virus replicating far more aggressively in the heart tissue of exercising animals.
In humans, the risk of sudden cardiac death rises during and within an hour after intense exercise, and respiratory viruses like COVID-19 have been shown to reduce aerobic capacity and cardiorespiratory function even after the fever resolves. The bottom line: rest completely while you have a fever. Save the workout for after your temperature has been normal for at least 24 hours, and ease back in gradually.
Don’t Ignore a Fever That Won’t Break
Most fevers from common infections resolve within three to five days. A fever that persists beyond that, keeps climbing despite medication, or comes with worsening symptoms is telling you something important. In adults, watch for a temperature that stays above 103°F, confusion or unusual drowsiness, a rash that appears alongside the fever, pain when urinating, or a stiff neck. In infants under three months, any fever of 100.4°F or higher needs prompt medical evaluation regardless of how the baby seems otherwise, because young infants can deteriorate quickly with limited warning signs.