Is ibuprofen toxic to cats? What to do now

Is ibuprofen toxic to cats?

Yes. Ibuprofen and other human anti-inflammatory painkillers, such as naproxen and aspirin, cause stomach ulcers and kidney damage in cats, often before you see anything wrong. Cats are affected at roughly half the dose that harms a dog, and a single tablet can be enough. Go to a vet now with the packet: treatment that starts before signs appear is the most effective.

Written by the Pativo team · Updated 14 November 2026

General information, not veterinary advice. If your pet may have eaten this, contact a vet now; do not wait for signs.

Go to an emergency clinic now if

Your cat swallowed or chewed any ibuprofen, naproxen or aspirin

Someone gave your cat a human painkiller

Vomiting, especially with blood or dark specks

Black, tarry stools or pale gums

Wobbling, tremors or a seizure

Your cat already takes a prescribed anti-inflammatory or steroid

Who to call

Your own vet first. If they are closed, the nearest emergency or out-of-hours clinic.

In the United States

Both answer 24 hours a day and may charge a consultation fee.

How Pativo rates this

Go now, whatever the amount

1Nothing alarmingWatch at home

2Worth watchingMonitor for a few days

3See a vet soonWithin 48 hours

4See a vet todayWithin 24 hours

5EmergencyGo now

This is the level the app answers with before it knows the amount. It comes from the app's own poison list, which runs on your phone.

Signs to watch for

Sign	Usually starts
Not eating, vomiting (sometimes with blood)	A few hours
Tummy pain, lethargy	A few hours to a day
Black, tarry stools	One to several days
Pale gums (bleeding ulcer)	One to several days
Drinking and urinating more or less (kidney damage)	Within a few days
Wobbling, tremors, seizures	Large amounts, hours

Why is ibuprofen toxic to cats?

Ibuprofen blocks prostaglandins, chemical messengers that also protect the stomach lining, keep blood flowing to the kidneys and support clotting. With that protection gone, the stomach can ulcerate and the kidneys can be starved of blood. Cats clear ibuprofen poorly because they have limited ability to process many drugs in the liver, so the drug lingers and does more harm than it would in a dog.

The same applies to other non-steroidal anti-inflammatory drugs (NSAIDs). The Merck Veterinary Manual notes that cats may be more susceptible to naproxen than dogs are and are very susceptible to aspirin, which stays in a cat's body for more than a day and a half.

How much ibuprofen is dangerous for a cat?

No safe amount has been set for cats, and a single standard tablet can be enough to harm one. Merck states that cats are poisoned at about half the dose that poisons a dog. Low doses mainly damage the stomach and gut; higher doses add kidney and liver damage; very high doses affect the brain and can cause seizures. Repeated small doses, for example from a well-meaning owner treating a limp, are dangerous too. A cat already on a prescribed anti-inflammatory or a steroid is at higher risk from any extra dose.

Which painkillers are dangerous for cats?

Any human non-steroidal anti-inflammatory is dangerous for a cat. That includes ibuprofen (sold as Advil, Nurofen, Brufen and many own-brand packs), naproxen, and aspirin, including low-strength aspirin taken for the heart. Gels, sprays and patches count too, because a cat swallows what it licks off skin or fur. Take whatever packet you have to the vet so they can see the exact drug and strength.

What will the vet do?

If the tablet was taken recently, the vet may make your cat vomit with an injection and give activated charcoal to reduce absorption. Most cats then need medicine to protect the stomach and a drip of intravenous fluids to protect the kidneys, with blood tests to check kidney and liver function. Stomach protection often continues for several days at home. Many cats recover well if treated quickly, but VCA notes that in some cases kidney or liver damage is permanent, and a bleeding ulcer can need a transfusion.

How do I stop it happening again?

Never give your cat a painkiller from your own cupboard. If your cat seems to be in pain, ask your vet for a medicine licensed for cats. Store tablets and gels in a closed cupboard, wash your hands after applying painkiller gel, and do not let your cat lick treated skin. Paracetamol is even more dangerous for cats: read why cats cannot take paracetamol. Dogs have their own page on ibuprofen poisoning in dogs.

Questions owners ask

Is ibuprofen gel dangerous to my cat?

It can be, because cats lick it off skin and fur. Keep your cat away from skin you have treated and call your vet if it licked any gel.

Is aspirin safer for cats than ibuprofen?

No. Cats are very sensitive to aspirin and clear it slowly. Never give aspirin unless your vet has prescribed it at a dose made for your cat.

Will my cat be all right if it seems fine now?

Not necessarily. Ulcers and kidney damage can develop over days without obvious signs, so a vet check and blood tests are needed even if your cat looks well.