Fevers in Cats


In this Article

  • Causes of a Fever in Cats
  • Signs of a Fever in Cats
  • Tips for Taking a Cat’s Temperature
  • Cat Fever Care

How can you tell if your cat has a fever? In humans, a kiss of a warm forehead may give you a clue. But you can’t tell if your cat has a fever by feeling for a warm, dry nose, as many people believe. The only way to know for sure — with either a human or a cat — is to take its temperature.

A normal temperature in cats ranges from 100.4º to 102.5º Fahrenheit. A fever in cats occurs when temperatures rise above 102.5º F. Although fevers may be helpful in fighting disease, a fever higher than 106º F can damage organs. Contact the vet right away if your cat has a high fever.

Learn about the causes, signs, and symptoms of fevers in cats and what you need to know about taking your cat’s temperature and caring for a cat with a fever.

Causes of a Fever in Cats

An increase in body temperature above normal is called hyperthermia. Abnormal or unregulated hyperthermia in cats may result from being in a very warm environment or having increased muscle activity, for example. However, a fever is a specific, regulated type of hyperthermia. It develops when the set point is increased in the hypothalamus, a part of the brain that acts as the body’s thermostat. A fever usually results when the immune system is activated by conditions such as:

  • A bacterial, viral, or fungal infection
  • A tumor
  • Injury from trauma
  • Certain medications
  • Diseases such as lupus

A fever for more than a few days with no apparent reason is called a fever of unknown origin (FUO).

Signs of a Fever in Cats

Diseases that cause a fever in cats can also cause certain telltale behaviors. These behaviors, which evolved in wild animals to help them survive illness, allow cats to conserve the necessary energy to produce a fever. Fevers fight disease by stimulating the immune system and slowing growth of bacteria and viruses.

Watch for these signs of a fever:

  • Loss of appetite
  • Depression
  • Lack of energy or activity
  • Decreased drinking
  • Hiding
  • Decreased grooming
  • Shivering or rapid breathing

Your cat may also display other specific signs of illness, such as sneezing, vomiting, or diarrhea.

Tips for Taking a Cat’s Temperature

The only way you can know for certain that your cat has a fever is to take their temperature.

A pediatric rectal thermometer is the most accurate method for taking a cat’s temperature. A digital thermometer is safer than a glass thermometer. It won’t shatter if you drop it, and it gives a signal when it’s time to check the reading. You can buy one from your vet or at the pharmacy.

1. Before you begin, get out all the supplies you’ll need:

  • The thermometer
  • A lubricant for the thermometer, such as petroleum jelly
  • Alcohol and paper towel to clean the thermometer
  • A cat treat

2. Shake a glass thermometer so the mercury is below the 96º line. To check, hold it up to the light and rotate it. To use a digital thermometer, turn it on.

3. Coat the tip of the thermometer with a lubricant.

4. Have a helper restrain your cat with the hind end facing you. Or if you are alone, cradle your cat’s body firmly against you with one arm.

5. Gently lift the tail and slowly insert the thermometer into the anus. Gently twist the thermometer from side to side to get the muscles to relax. Once this occurs, insert the thermometer about one inch into the rectum, but do not force it.

6. Remove a digital thermometer when you hear the beep. Leave a glass thermometer in place for about two minutes.

7. Remove and clean the thermometer with alcohol. Read the temperature, holding a glass thermometer to the light and rotating it.

8. Give your cat a treat if your cat has not been vomiting.

Cat Fever Care

Cats exhibiting signs of a fever for more than 24 hours or a fever above 104º F at any point need to see their veterinarian. The veterinarian may conduct tests to determine the source of the fever and take steps to treat the underlying problem. If a bacterial infection is the source, for example, antibiotics may be needed. Moderate or severe dehydration is treated with the administration of intravenous or subcutaneous fluids.

Never give your cat medication without the advice of your veterinarian. Some medications for fever, such as acetaminophen, are toxic to cats.

Show Sources


Cornell University College of Veterinary Medicine: “Taking Your Cat’s Temperature”.

WSAVA Congress: “Diagnosis and Management of Fever in Cats”.

The Merck Veterinary Manual: “Fever of Unknown Origin”.

Hart, B. CCAH Update. “Behavior of Sick Dogs and Cats”.

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