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

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.