Updated September 25, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Never give a dog or cat a human fever reducer. Acetaminophen (Tylenol) can kill a cat, even in a small amount, and damages dogs’ livers. Ibuprofen and naproxen cause stomach ulcers and kidney failure, and aspirin is risky, especially for cats. Normal body temperature for dogs and cats is about 100.5–102.5°F (38–39.2°C). A fever over about 103°F (39.5°C) means your pet should see a vet, and over 105°F (40.5°C) is an emergency.
How to check your pet’s temperature
- Use a digital rectal thermometer with a little petroleum jelly or water-based lubricant.
- Insert gently about 1 inch (less for small pets and cats), and hold until it beeps.
- Ear thermometers made for pets are an option but may be less accurate.
- If your pet is struggling or you’re worried about being bitten, skip it and call your vet.
Fever vs. overheating
- Fever is the body raising its temperature to fight infection or inflammation.
- Heatstroke is overheating from hot weather or exercise. Signs include heavy panting, drooling, bright red or pale gums, weakness, vomiting, and collapse. It’s an emergency.
If you suspect heatstroke
- Move your pet to shade or air conditioning.
- Wet the body with cool (not ice-cold) water and use a fan.
- Offer small amounts of water if your pet is alert.
- Head to a vet right away, cooling on the way.
Common causes of fever
- Infections (bite abscesses, urinary, respiratory, tick-borne diseases)
- Inflammation, such as pancreatitis or immune-related conditions
- Some cancers
- Reactions to vaccines (mild and short-lived)
When to see a vet
- Temperature above about 103°F, or below 99°F
- Fever lasting more than a day, or with other signs like not eating, vomiting, or lethargy
- Emergency: temperature above 105°F, collapse, seizures, or signs of heatstroke
How vets treat fever
- Finding and treating the cause, such as antibiotics for bacterial infections or draining an abscess
- IV or subcutaneous fluids
- Veterinary anti-inflammatory medications, when appropriate for your pet’s species and health
Safe home care while you arrange a vet visit
- Keep fresh water available.
- Provide a cool, quiet resting place.
- Offer food, but don’t force it.
What to avoid
- Acetaminophen (Tylenol): deadly to cats and harmful to dogs.
- Ibuprofen (Advil, Motrin) and naproxen (Aleve): can cause ulcers and kidney failure.
- Aspirin: only if your vet specifically prescribes it. Especially risky for cats.
- Cold medicines, which often contain these drugs plus decongestants.
- Ice baths or rubbing alcohol, which can cause dangerous overcooling.
If your pet swallowed a human medication, call your vet or a pet poison hotline right away: ASPCA Animal Poison Control Center (888) 426-4435 or Pet Poison Helpline (855) 764-7661 (fees apply).
Frequently asked questions
Can I tell if my dog has a fever by feeling its nose?
No. A warm or dry nose isn’t a reliable sign. A thermometer is the only accurate way.
Can I give my dog baby aspirin for a fever?
Not without your vet’s advice. It can cause stomach bleeding and interacts with other medications.
Sources
- Merck Veterinary Manual: Fever in animals
- ASPCA Animal Poison Control Center: Acetaminophen and NSAID toxicity
- Merck Veterinary Manual: Heatstroke in small animals
- Pet Poison Helpline: Acetaminophen
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.