How to Tell If a Dog Has a Fever

While a drippy nose and a case of the shakes might mean your dog's running a fever, only a rectal thermometer can tell for sure. Your pup's probably not going to be a fan of the thermometer, so having a friend or spouse makes the process much easier.

Lubricate the top two inches of the thermometer with a lubricating substance. Petroleum jelly works well and is sold in plenty of stores. Do not use water or soap, because water is not a lubricant and soap can irritate your dog's rectum.

Tell your pup to stand if he knows the command. If he doesn't, grab his attention by standing a few feet in front of him and luring him over by playfully clapping or waving a treat in front of him. As soon as he springs to action, command him to stay. If he doesn't know that command, ask someone to place their hands on both sides of his body, a bit past the shoulder blades.

Move into position behind your dog and lift his tail. Turn on the thermometer and slowly and carefully insert the tip one to two inches into his rectum. Modern dog rectal thermometers are tiny, so you should have no issue inserting it, but that doesn't mean your pup will enjoy the experience. He'll probably try to leave immediately. Keep him calm by petting and praising him.

Wait until the temperature registers, which the thermometer will indicate by beeping, and remove it from your dog's rectum. It usually takes anywhere from 30 to 60 seconds for the temperature to register. If your dog's temperature is any higher than 103 degrees Fahrenheit, your little guy is running a fever. A temperature of 106 degrees Fahrenheit or higher can be deadly.

Contact your vet if your dog has a fever, even a slight one that's just over 103 degrees Fahrenheit. He'll likely ask you to bring him in at some point, but to monitor his temperature until you do. WebMD suggests cooling off your dog if his temperature creeps past 105 degrees Fahrenheit by wetting his entire body with cold water and putting a fan in front of him. After his temperature dips back into the 103 degrees Fahrenheit range, he's cooled off enough that you no longer need to water him like a thirsty houseplant, but do keep checking his temperature to make sure it doesn't skyrocket.

Items you will need

  • Digital dog rectal thermometer
  • Lubricating substance


  • Always use a digital rectal thermometer that's specifically for dogs.
  • Tell your vet everything your dog did just before his fever occurred. Sometimes an unknown illness can cause a fever, but other times it's due to high heat or something your dog ate. The more your vet knows, the faster he can make a diagnosis and put your little guy on the road to recovery.
  • Don't get frustrated with your dog if the process takes a while. Some dogs are not cooperative, but a bit of patience will help a lot more than yelling at or getting angry with your pup.


  • If your pup's temperature reaches 106 degrees or higher, rush your dog to the vet or the nearest pet emergency facility immediately. At this stage, it's too dangerous to try and lower your dog's temperature on your own.

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About the Author

Located in Pittsburgh, Chris Miksen has been writing instructional articles on a wide range of topics for online publications since 2007. He currently owns and operates a vending business. Miksen has written a variety of technical and business articles throughout his writing career. He studied journalism at the Community College of Allegheny County.