Can I Give My Dog Aspirin?

No
Aspirin causes stomach ulcers and bleeding in dogs, and it is no longer recommended now that safer canine NSAIDs exist. If a vet has not specifically told you to give it, skip it. One adult human tablet can be several times too much for a small dog.
Source: Pet Poison Helpline
Already ingested? Pet Poison Helpline 855-764-7661

Cats are different

Do not carry this answer over to your cat: for cats, Aspirin falls under “do not give at home.” Species handle drugs differently, and the dog answer on this page applies to dogs only.

About Aspirin

Aspirin is on the do-not-give list: there is no safe at-home dose. Reference data on this page reflects published veterinary sources, not a prescription for your dog.

What to have ready when you call the vet

Whether you are confirming a dose or reporting that your dog already got into something, the call goes faster with four facts ready: your dog's current weight, the exact product name and strength from the label, how much was given or eaten, and roughly when. With those, most clinics can answer in one call.

The safe habit

Confirm any medication decision with your veterinarian, who knows your dog's health history and other medications. VetDose shows published reference data, not prescriptions.

See also

Other danger (no safe home dose) questions for dogs