Is Naproxen Toxic to Cats and Dogs?
Naproxen is severely toxic to cats and dogs — it lingers in the body for days, causing stomach ulcers and kidney failure. Call a vet immediately.
Potentially life-threatening — treat any exposure as an emergency.
Potentially life-threatening — treat any exposure as an emergency.
In an emergency, do not wait.
Medical disclaimer: This tool is for general information only and isnot a substitute for veterinary diagnosis or treatment. Toxicity depends on the amount, your pet’s size, and health history. If your pet may have ingested something harmful, contact your veterinarian or a poison control hotline ((888) 426-4435 / (855) 764-7661) immediately — do not wait for symptoms to appear.
What is Naproxen?
Naproxen is severely toxic to cats and dogs — it lingers in the body for days, causing stomach ulcers and kidney failure. Call a vet immediately.
Also known as: aleve, naprosyn, midol, nsaid, anaprox.
Symptoms to Watch For
🐕 In Dogs
- Vomiting, sometimes with blood
- Stomach ulcers and abdominal pain
- Kidney injury with changes in thirst and urination
- Lethargy and weakness
🐈 In Cats
- Vomiting and drooling
- Stomach ulcers and pain
- Kidney failure (cats are highly sensitive)
- Lethargy and loss of appetite
What to Do If Ingested
- Call a veterinarian or poison hotline immediately — naproxen lingers in the body for days.
- Note the mg strength and number of pills eaten.
- Do not induce vomiting unless a vet directs it.
Steps apply to both cats and dogs. When in doubt, call a vet or poison hotline before acting.
When to Call the Vet Immediately
Call your veterinarian or a poison control hotline right away if you notice any of these:
- Any naproxen was eaten
- Vomiting, especially with blood
- Reduced or absent urination
- Lethargy, belly pain, or weakness
Frequently Asked Questions
Frequently Asked Questions
Why is naproxen especially dangerous?
Naproxen stays in a dog's body far longer than in a human (half-life up to 74 hours in dogs), so toxicity can be prolonged. It causes stomach ulcers and kidney injury even at relatively small doses. Call a vet right away with the strength and number of pills.
What are the signs of naproxen poisoning?
Vomiting (sometimes with blood), diarrhea, belly pain, and loss of appetite from stomach ulcers, followed by kidney injury shown by changes in thirst and urination. Because the drug lingers, symptoms can persist for days without treatment.
Should I induce vomiting after naproxen ingestion?
Only if a veterinarian or poison control professional tells you to. Naproxen is absorbed and can irritate the stomach, so inducing vomiting without guidance can cause more harm. Call first and follow their instructions.
Sources
This entry is reviewed against the following authoritative veterinary sources.
Last reviewed: 2026-07-11