Although it may not seem like it, fever is your friend. That’s because in most cases, fever is a vital part of your body’s defense against infection and inflammation.

When bacteria and viruses invade your body and cause infections, your body tries to kill them off by raising its normal core temperature. In short, the fever is fighting the battle for you, not against you.

Keep in mind that an adult’s normal body temperature may change during an average day. There are a number of reasons for this, including a woman’s menstrual cycle, certain medicines, physical activity, high humidity—even eating.

You’re probably running a fever when your temperature stays above 99°F to 99.5°F

How to treat a fever at home

According to Pam Kraft, a nurse practitioner with Kettering Health, sometimes you may not even need to treat a fever. Kraft explains that “Low-grade fevers typically don’t need treatment. It’s when the fever starts to make you feel uncomfortable or reaches higher levels—such as 101.5°F and higher—that you should consider treatment.”

You can treat a less-serious fever by

• Drinking large amounts of fluid
• Cooling yourself off with a fan
• Taking a cool shower
• Applying a lukewarm, damp cloth to your forehead or the nape of your neck

“If you safely use over-the-counter drugs such as acetaminophen (Tylenol) and nonsteroidal anti-inflammatories (or NSAIDs, such as ibuprofen) for other ailments, you can try using them to bring down a fever as well,” Pam says. “You can even alternate acetaminophen and NSAIDs throughout the day. Just be sure to follow the dosage instruction on the label.”

Fever warning signs: when it’s time to see a doctor

Call your doctor right away or visit an urgent care if you’re experiencing these symptoms.

• A fever that
  • Lasts more than three days
  • Doesn’t respond to medicines
  • Rises very rapidly
• Feelings of disorientation or confusion
• A rash that appears with the fever and spreads
• Chest pain or trouble breathing
• Constant vomiting

Why you’ll want to stay on top of those symptoms

A fever that won’t go away could be a sign of a more serious health problem, such as

• Urinary tract infection (UTI)
• A reaction to medicine
• Stress
• Chronic fatigue or fibromyalgia
• Tuberculosis
• Autoimmune disease
• Thyroid issues
• Some cancers

“This is why it’s important to follow up with your primary care provider if a fever persists longer than three days,” added Kraft.

Temperature tips

“Taking a temperature rectally has the most accurate results, but it’s less convenient and less tolerated by children—and adults,” said Kraft. Instead, she recommends taking your temperature by ear, since it’s the next-closest core temperature and the most convenient option.

Remember, a normal temperature can vary from person to person. “A patient who says their temperature typically runs a little lower may not feel well at 99.9°F. Whereas someone who may normally run 98.9°F may feel fine at 100.5°F,” Kraft explained. “We are all still individuals and need to be treated as such.”