Dogs can be given aspirin once or twice a day for short-term pain relief only. Large dogs weighing 50 to 100 pounds can be given one regular aspirin tablet and dogs over 100 pounds can be given two regular aspirin. Walker Valley Veterinary Hospital states that dogs between 30 to 50 pounds can be given one-half of a regular aspirin tablet. Smaller dogs should be given baby aspirin; one-half a baby aspirin tablet for dogs under 10 pounds and one baby aspirin for dogs that are 10 to 30 pounds.
Walker Valley recommends giving aspirin with food and suggests using buffered aspirin as it is easier on the dog's stomach. Consult with a veterinarian if long-term pain relief is needed. Vetstreet warns that dogs can be poisoned by aspirin if they consume too large a dose. Most cases of aspirin toxicity in dogs occur after a dog accidentally gets hold of a bottle of aspirin and consumes several tablets.