Why they're risky
Ibuprofen (Advil, Nurofen) and naproxen (Aleve) are NSAIDs. In dogs they can cause stomach ulcers at relatively low doses and kidney injury at higher ones. Naproxen lasts much longer in a dog's body than in a person's, which makes it especially dangerous. According to the Merck Veterinary Manual, stomach problems in dogs can appear from about 25 mg/kg of ibuprofen, kidney injury from roughly 175 mg/kg, and nervous system signs at higher doses still. For a 10 kg dog, one 200 mg tablet is already 20 mg/kg.
Paracetamol (acetaminophen)
Paracetamol isn't an NSAID, but it can damage the liver and red blood cells in dogs. In cats it is extremely dangerous even in small amounts: never give it to a cat.
Signs of poisoning
- Vomiting, sometimes with blood or "coffee grounds"
- Black, tarry stools
- Not eating, belly pain, lethargy
- Drinking and peeing more, then less (kidney signs)
- With very large doses: wobbliness, seizures
What to do
Count the missing tablets, note the strength, and call your vet or a poison line now. Vets typically make the dog vomit, give activated charcoal, start stomach protectants, and often run IV fluids for 48 hours to protect the kidneys, with blood tests afterwards.
Safer pain relief
Dogs have their own NSAIDs (such as carprofen or meloxicam) dosed for their bodies. Your vet can prescribe the right one after checking kidney and liver health. For allergies, some vets do recommend plain diphenhydramine: see the Benadryl dosage calculator, and always check with your vet first.
Frequently asked questions
Can I give my dog baby aspirin?
Only on your vet’s advice. Aspirin can still cause stomach bleeding, and it interferes with the safer dog-specific pain medicines.
My dog ate one ibuprofen. Is that an emergency?
It depends on your dog’s weight and the tablet strength. For small dogs one tablet can be significant, so call your vet or a poison line right away.