Is Naproxen Dangerous to Dogs?
Yes. Naproxen (Aleve) is among the most dangerous human painkillers for dogs — even a small amount can cause stomach ulcers and kidney failure.
Quick facts
| Verdict | Toxic |
|---|---|
| Risky amount | No safe or toxic dose is established — treat any amount as a risk. |
| Key symptoms | Vomiting (sometimes with blood), Black, tarry stool, Loss of appetite, Weakness or pale gums, Increased thirst and urination, Lethargy |
| What to do | If your dog swallowed naproxen, call your vet or a pet poison hotline immediately — even for a partial tablet. Early decontamination and fluids can prevent ulcers and kidney failure; waiting for symptoms may be too late. |
Why naproxen is a top-tier dog poison
Naproxen is an NSAID like ibuprofen, but harder on dogs in two ways. First, dogs eliminate it extremely slowly, so one tablet keeps circulating and doing damage for days. Second, its safety margin is so narrow that doses trivial for a human can ulcerate a dog’s stomach and injure the kidneys. That is why poison control centers treat any canine naproxen ingestion as significant, regardless of the dog’s size.
What it does inside a dog
Naproxen blocks the prostaglandins that protect the stomach lining and keep blood flowing through the kidneys. The stomach damage shows first — vomiting, blood in vomit, black digested-blood stool, refusing food. Kidney injury tends to follow, showing up as increased thirst and urination, then lethargy as failure develops.
What to do if your dog ate naproxen
Call your vet or a pet poison hotline immediately, even if your dog seems fine — early signs lag behind the damage. Bring the packaging so the clinic knows the strength. Treatment usually means decontamination if recent, stomach protectants and IV fluids to defend the kidneys, sometimes for several days because the drug lingers. Never give naproxen, ibuprofen or paracetamol as home pain relief — ask your vet for a canine NSAID instead.
If your dog ate it
If your dog swallowed naproxen, call your vet or a pet poison hotline immediately — even for a partial tablet. Early decontamination and fluids can prevent ulcers and kidney failure; waiting for symptoms may be too late.
In the US you can also call the ASPCA Animal Poison Control Center at (888) 426-4435 (a consultation fee may apply).
Frequently asked questions
- Why is naproxen worse for dogs than ibuprofen?
- Naproxen stays in a dog's body far longer than in a human's, so a single dose keeps damaging the stomach lining and kidneys for days. Combined with a very narrow safety margin, that makes it one of the most dangerous common medications for dogs.
- My dog ate one Aleve. Do I really need the vet?
- Yes. One tablet is enough to cause stomach ulcers and, in smaller dogs, kidney injury. Call your vet or a poison hotline right away with your dog's weight and the tablet strength — early treatment changes the outcome.
- What are the first signs of naproxen poisoning in dogs?
- Vomiting (sometimes with blood), loss of appetite, black tarry stool and lethargy usually come first, often within hours to a day. Kidney signs like drinking and urinating more can follow over the next days.
- Can any dog take naproxen at a small dose?
- No. There is no accepted safe dose of naproxen for dogs. Vets use dog-specific NSAIDs instead, which are designed for canine metabolism and monitored properly.
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