Aspirin for Dogs: A Pain Medication With a High Risk of Serious Side Effects

Many people have aspirin in their medicine cabinet. You may give this medication to your human family members to manage their aches, pains, and fevers. If so, it’s only natural to wonder whether you can safely use aspirin to help your canine companion. 

So is aspirin a good choice for dogs? It’s usually not the best medication for dogs because it can lead to serious side effects. Read more about aspirin for dogs, below.

Aspirin for dogs at a glance

What is aspirin for dogs, and how does it work?

Aspirin is a nonsteroidal anti-inflammatory drug (NSAID). Aspirin inhibits an enzyme called cyclooxygenase (COX). By inhibiting COX, aspirin blocks the production of prostaglandins, which are chemical signals produced by the body. 

Prostaglandins play a number of roles in the body, but they are primarily involved in the following processes: 

• Pain

• Inflammation/swelling

• Fever

• Blood clotting 

As a result, aspirin reduces pain, inflammation, fever, and blood clotting. 

What is aspirin used for in dogs?

While aspirin is occasionally used to treat pain, inflammation, fever, and blood clotting in dogs, its use in canines is rare. 

Aspirin is associated with a high risk of side effects, especially when compared to other NSAIDs for dogs. So veterinarians typically reach for safer NSAIDs and use aspirin sparingly (if at all). 

Aspirin can be purchased over the counter in many stores, including some pet stores. This may lead you to think this medication is safe for use in dogs. But, as mentioned above, aspirin has a high risk of side effects, especially gastrointestinal ulcers. Do not give aspirin to your dog without first consulting your veterinarian. 

What is the typical dosage of aspirin for dogs, and how is it given?

Aspirin is given to dogs in tablet form. The recommended aspirin dosage for a dog depends on their body weight and the condition being treated. For example, the dosage used to prevent blood clotting is much lower than the dosage used for pain. If your veterinarian prescribes your dog aspirin, they will calculate the best dosage for your pet.

Follow your veterinarian’s directions carefully to reduce the risk of side effects. Do not try giving your dog aspirin without first talking to your vet. As mentioned, aspirin can cause serious side effects in dogs if not given correctly.

What should you do if your dog misses a dose of aspirin?

If you forget to give your dog a dose of aspirin, you can give them the medication as soon as you remember. But then delay the next dose accordingly, so there’s the correct amount of time in between. 

If it’s almost time for your dog’s next dose when you remember, skip the missed one and continue with their regular medication schedule.

What are common side effects of aspirin in dogs?

The most common side effects of aspirin in dogs include: 

• Nausea

• Vomiting

• Diarrhea

If your dog develops these digestive side effects, stop giving them the medication and contact your veterinarian. 

What are the most serious risks of aspirin for dogs?

Dogs can experience serious side effects from aspirin. This is why veterinarians often avoid the NSAID, especially for dogs with gastrointestinal disease, kidney disease, or suspected clotting disorders. Veterinarians typically use other, safer medications when possible. 

The most common serious side effect of aspirin in dogs is gastrointestinal ulcers and bleeding. Almost all dogs who are treated with aspirin develop bleeding ulcers, though these ulcers don’t necessarily cause symptoms. 

Gastrointestinal ulcers can lead to significant blood loss in dogs. They can also perforate or rupture, requiring emergency surgery. 

Other serious risks associated with aspirin in dogs include: 

• Acute kidney failure

• Excessive bleeding 

• Seizures (with high dosages)

• Liver failure (with high dosages)

The side effects associated with aspirin can be serious and even deadly for dogs. As a result, veterinarians monitor dogs closely while they’re taking aspirin. 

If your vet prescribes your dog aspirin, they may recommend regular checkups and blood tests. They may also talk to you about signs of serious side effects to watch for at home. 

Does aspirin interact with any other dog medications?

Aspirin can interact with many other dog medications. Some interactions may lead to an increased risk of side effects, while others can decrease how well either medication works. 

Medications that may react with aspirin include: 

• Prednisone and other steroids

• Other NSAIDs, such as meloxicam and carprofen

• Diuretics, such as furosemide

• Anticoagulants

• Digoxin

• Tetracycline

Make sure your veterinarian is aware of any medications your dog is taking. This includes prescription medications, over-the-counter medications, and supplements. 

Do not give over-the-counter aspirin to your dog unless your veterinarian tells you to do so. 

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Written by:

Catherine Barnette, DVM

Catherine Barnette, DVM, is a small animal veterinarian with 14 years of experience providing preventive care, medical workups, and surgical services in a number of general veterinary practices. She also served on her county's board of health for several years and taught biology laboratories for college students.

Edited by:

Renée Fabian, MA

Renée Fabian is the senior pet health editor at GoodRx. She’s worked for nearly 10 years as a journalist and editor across a wide range of health and well-being topics.

Reviewed by:

Ghanasyam Bey, DVM

Ghanasyam Bey, DVM, is from Cleveland, Ohio, and attended Princeton University for undergraduate studies. After a year of biology research at Duke University, he attended Ohio State College of Veterinary Medicine.

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