Taking care of someone who is sick and feverish can be a worrying experience — especially if they’re very young, very old, or vulnerable to immune system challenges.

Anxiety may escalate if the person begins to see and hear things that aren’t really there. Hallucinations sometimes happen when people have high fevers.

Most of the time, fever hallucinations resolve on their own as the fever comes down, but it may help to know what you can do at home and when you should seek medical attention if symptoms don’t improve.

Fever is a sign of inflammation, and it’s part of the body’s immune response. It’s often accompanied by chills and sweating. Some people also experience disorientation, strange dreams, seizures, and hallucinations with a fever.

On their own, fever hallucinations themselves aren’t dangerous, even though they can be frightening.

Most of the time, these hallucinations involve seeing images or hearing sounds that aren’t present outside of the person’s mind. Occasionally, people have hallucinations in which they feel, taste, or smell things that aren’t real.

While hallucinations aren’t dangerous, treating the illness that is causing both fever and hallucinations can help resolve the problem.

Fever hallucinations usually pass in a few minutes. If confusion, delirium, and hallucinations don’t go away, it’s important to get medical care.

Delirium, fever, and hallucinations have been associated with COVID-19 in some cases. Fever and hallucinations may also be a problem for people with Alzheimer’s disease.

Brain and spinal cord infections

Some brain and spinal cord infections, such as meningitis and encephalitis, can cause both fever and hallucinations.

Meningitis is an inflammation of the spinal cord caused by a bacterial or viral infection. Encephalitis is an inflammation of the brain caused by viruses and bacteria. Rarely, these conditions may also be caused by a fungal infection.

Both conditions can quickly become serious or even life threatening, so it’s important to get medical care right away if you or some in your care experiences symptoms like these:

  • sudden, severe headache
  • high fever
  • disorientation and confusion
  • nausea and vomiting

A slight fever will usually resolve on its own within 1 to 2 days, especially if you’re otherwise in good health.

To bring down a fever, you might want to try some over-the-counter remedies. Be sure to talk to your healthcare provider about any allergies or health conditions before you try any of these:

  • Acetaminophen. Tylenol, paracetamol, and other pain relievers containing acetaminophen can be effective fever reducers. Follow dosage guidelines carefully, because using too much acetaminophen can be harmful to your health. Talk to your child’s healthcare provider about using acetaminophen with an infant.
  • Ibuprofen. Advil, Motrin, and other anti-inflammatory medications can also lower a fever. Again, pay close attention to dosage amounts and talk to your child’s healthcare provider about medicating infants under 6 months.
  • Lots of fluids. When your body temperature gets too high, you can become dehydrated more quickly. Drinking cool liquids can keep you hydrated and may make you feel more comfortable.
  • Tepid baths. Don’t be tempted to step into an icy bath to lower your temperature. Instead of cooling you off, water that’s too cold could trigger bouts of shivering, which may actually raise your temperature instead. Try lukewarm or tepid baths to make yourself feel cooler.
  • Cool compresses. Ice packs and cool compresses probably won’t lower your core body temperature or resolve a fever, but they may make you feel better as you recover.

Most low-grade fevers and hallucinations resolve on their own. If you or someone in your care is experiencing these symptoms (with or without hallucinations), it’s time to talk to your doctor:

  • adults with a fever over 103°F (39.4°C)
  • children with a fever of over 102°F (38.9°C)
  • babies with fever over 100.3°F (37.9°C)
  • fevers that persist longer than 48 hours
  • severe headache or earache
  • painful, stiff neck
  • confusion
  • chest pain
  • rash
  • painful urination
  • exposure to extreme heat outdoors
  • cough with bloody, green, or brown mucus
  • trouble breathing
  • severe stomach pain and vomiting

Fever is your body’s response to inflammation.

Sometimes, mental confusion and hallucinations happen when people have a fever. These fever hallucinations may involve seeing or hearing things that aren’t there — which can be uncomfortable for caregivers and patients alike.

Fever hallucinations aren’t dangerous on their own. If a fever doesn’t go away after 2 days, or if it gets higher than 103°F (39.4°C) in adults, 102°F (38.9°C) in children, or 100.3°F (37.9°C) in infants younger than 3 months, it’s time to see a healthcare provider.

Fever reducers like acetaminophen and ibuprofen are usually effective, but it’s important to follow dosage and age recommendations for their use. Be sure to stay hydrated when you have a fever, as well. Cool baths and cold compresses may help you cool down.

Some potentially serious infections and health conditions can cause both fever and hallucinations. Severe headache, neck pain, rashes, and breathing difficulties can signal that you need to seek medical attention immediately.

On their own, however, feverish hallucinations aren’t harmful. With rest, liquids, and medical care as needed, they usually go away on their own.