No. Never give your cat Tylenol (acetaminophen), ibuprofen (Advil, Motrin), naproxen (Aleve) or aspirin unless your vet has prescribed that exact drug at that exact dose. Cats process these medicines very differently from people and dogs, and the ASPCA Animal Poison Control Center warns that a single regular-strength Tylenol tablet can be enough to kill a cat.
If your cat has already swallowed one, skip the rest of this article for now: call your vet, an emergency clinic, or a pet poison line (numbers below) right away. Acetaminophen and NSAID poisoning are both treatable, and outcomes are far better when treatment starts early.
Why is Tylenol so dangerous for cats?
It comes down to liver chemistry. People clear most of a dose of acetaminophen through a liver pathway called glucuronidation. Cats are genetically short on one of the key enzymes for that pathway (the UGT1A6 gene doesn’t work properly in cats, a finding published in Pharmacogenetics and Genomics in 2005). Without it, more of the drug gets shunted into a route that produces a toxic by-product, and the cat’s small reserves of glutathione, the molecule that normally neutralises it, run out fast.
The result, as described in the Merck Veterinary Manual, is damage to red blood cells. Hemoglobin gets converted to methemoglobin, which can’t carry oxygen, and the cells break down. Signs usually start within a few hours:
- Brown, muddy or bluish gums
- Fast or laboured breathing
- Swelling of the face and paws
- Drooling, vomiting, weakness
- Dark or brown urine
Liver damage can follow, but in cats it’s the blood problem that tends to cause the crisis. There is an antidote (N-acetylcysteine) plus supportive care, which is why getting to a vet quickly matters so much.
What about ibuprofen, naproxen and aspirin?
These are NSAIDs (non-steroidal anti-inflammatory drugs), and they’re dangerous to cats for a different reason. NSAIDs reduce the protective mucus and blood flow in the stomach lining and reduce blood flow to the kidneys. Cats clear many NSAIDs slowly, so a dose that’s routine for a person builds up. The two big risks are:
- Stomach and intestinal ulcers: vomiting (sometimes with blood), black tarry stool, not eating
- Acute kidney injury: drinking and peeing more or much less, lethargy, vomiting
Naproxen is especially long-acting, and ibuprofen tablets are sized for a 150-pound human, not a 10-pound cat.
Aspirin is the confusing one, because you may have read that vets use it in cats. Some vets do occasionally prescribe it, for example in certain heart conditions where clots are a risk, but at very small doses spaced days apart, because cats take far longer than people to clear it. That’s exactly why a home-guessed dose is risky. If aspirin is right for your cat, your vet will tell you the dose and the schedule.
The less obvious human medications that poison cats
Pain relievers get the headlines, but they’re not the only problem in the medicine cabinet. The ASPCA’s poison control team regularly lists these among common cat exposures:
- Antidepressants, particularly venlafaxine (Effexor). ASPCA toxicologists have reported that cats seem drawn to the capsules and will eat them on their own, possibly because of the smell or coating.
- ADHD medications (amphetamine-based stimulants), which can cause agitation, tremors, high heart rate and seizures.
- Topical creams and gels. In 2015 the US FDA warned that cats had become ill or died after exposure to prescription pain creams containing the NSAID flurbiprofen, simply from licking it off their owner’s skin or from contact with treated areas. The same caution applies to diclofenac gels (like Voltaren) and to hormone creams.
- Cold and flu tablets that combine acetaminophen with decongestants. Check labels: acetaminophen is hidden in a lot of combination products.
The common thread is easy access. A pill dropped on the floor, an open weekly organiser on the bench, or a blister pack that becomes a toy. Our kitten-proofing checklist and the guide to household chemicals that are toxic to cats cover the rest of the house, and our piece on essential oils and cats explains another liver-related blind spot cats have.
My cat is in pain. What can I actually give them?
Nothing from your own cabinet. But the good news is that cat pain relief has improved a lot, and your vet has real options:
- Cat-specific NSAIDs. In the US, robenacoxib (Onsior) is approved for short-term use in cats, and meloxicam is approved as a single injection. Both are dosed by weight and used with kidney function in mind. Note that meloxicam’s US label carries a warning against repeated doses in cats, so even “pet” NSAIDs are a vet’s call, not a leftover-from-the-dog’s-prescription call.
- Frunevetmab (Solensia), a monthly injection for arthritis pain, approved by the FDA in 2022. It isn’t an NSAID at all.
- Other pain medicines such as buprenorphine or gabapentin, which vets prescribe for specific situations.
And never share your dog’s medication. Carprofen and other dog NSAIDs are dosed for dogs’ metabolism and have caused serious illness in cats.
Cats are also notoriously good at hiding pain, so if you’re wondering whether yours hurts at all, our guide on how to tell if your cat is in pain walks through the signs vets look for, and there’s a separate one on pain in older cats.
What to do if your cat swallowed a human pill
- Move your cat away from any other pills and gather up the packaging. Note the drug name, strength and roughly how many might be missing.
- Call for help immediately, even if your cat looks fine. Signs can take hours to appear, and treatment works best before they do.
- Your vet or nearest emergency vet clinic
- ASPCA Animal Poison Control Center: (888) 426-4435
- Pet Poison Helpline: (855) 764-7661
(Both poison lines charge a consultation fee.)
- Don’t try to make your cat vomit at home. Hydrogen peroxide, the trick sometimes used for dogs, is not recommended for cats and can cause serious stomach inflammation. Salt and fingers down the throat are dangerous too. If your cat needs to vomit, a vet will use medication to do it safely.
- Take the packaging with you if you’re told to come in.
When to see a vet
Treat any of these as an emergency, whether or not you saw your cat take anything:
- Brown, grey or blue gums or tongue
- Swollen face or paws
- Breathing fast, with an open mouth, or with effort
- Vomiting blood, or black tarry stool
- Sudden weakness, collapse, tremors or seizures
- Not eating, or a big change in drinking or peeing after a possible exposure
And book a regular appointment if your cat seems sore, stiff or out of sorts. Pain is worth treating, just with the right drugs.
The short version
Human pain relievers and cats don’t mix. Keep every medication shut away, take pills over a sink or closed surface so a dropped tablet can’t roll off, wash your hands after applying any medicated cream, and ring a vet or poison line the moment you suspect your cat has swallowed something. If your vet does prescribe medicine, our step-by-step guide on how to give a cat a pill will save you some scratches.
Where do you keep your medications at home, and has your cat ever gone after something in the medicine cabinet?