Cat healthPoisoningMedicines

Why paracetamol (Dolo, Crocin, Calpol) is dangerous for cats

Cats have a limited ability to clear paracetamol, so Dolo, Crocin or Calpol can damage their blood and liver. Any amount is a reason to call a vet.

··8 min readEditorial

Paracetamol (acetaminophen) is especially dangerous for cats. A cat has a limited ability to clear it, so toxic by-products build up and damage the red blood cells and the liver. Dolo, Crocin and Calpol are all paracetamol, so if a cat has swallowed or been given any, treat it as an emergency and call a vet now.

What to do right now

If your cat may have swallowed any paracetamol product, do these things in this order.

  • Phone your vet or the nearest veterinary hospital now. Do not wait to see whether signs appear. The ASPCA advises getting help even when signs are mild or absent.
  • Do not make your cat vomit. The ASPCA says trying to induce vomiting at home can be dangerous, that hydrogen peroxide should not be given to cats, and that there is nothing that can be given at home to safely make a cat vomit. Salt, olive oil and a finger down the throat should not be used on any pet. A vet decides whether and how to remove a medicine from the stomach.
  • Do not try home remedies. The ASPCA says ipecac is very unsafe for pets, and that milk and water do not work to make a pet vomit.
  • Take the strip, bottle or box with you. The ASPCA says its poison-control staff ask about the product package, the strength of the ingredients, the amount the pet was exposed to, and the pet’s weight and health history. These details are for the vet to use, not for you to judge whether it matters.
  • Go straight to a veterinary hospital if your cat has a seizure, has trouble breathing, does not respond to you, or is bleeding. Tell the vet at once if the gums look brown, muddy or bluish, which Merck lists among the signs.

We have not verified any 24-hour animal poison helpline in India, so this article lists none. Phone your own vet or the nearest veterinary hospital.

Why cats cannot handle paracetamol

The body clears paracetamol mainly in two ways. One is glucuronidation, which relies on an enzyme called glucuronyl transferase. The other is sulfation. According to the Merck Veterinary Manual, cats have low glucuronyl transferase activity, so they rely mostly on sulfation. When that route is overloaded, toxic by-products are produced.

That is the whole problem in one sentence: the cat has only one main route, and it overloads. Pet Poison Helpline says paracetamol is safe for people but that this is not true for pets, especially cats. On its acetaminophen page it adds that paracetamol has a narrower margin of safety in dogs and is especially dangerous for cats.

This is also why the question “what is the cat dose?” has no useful answer. A cat is not a small dog. The ASPCA has a whole article on why species matters for pet toxins, and it lists acetaminophen and aspirin among the toxins that affect cats differently.

What paracetamol does inside a cat

Blood levels of paracetamol usually peak within about an hour of swallowing, and slow-release products delay that peak. In cats, the Merck Veterinary Manual says methaemoglobinaemia develops within a few hours and that Heinz-body formation follows. Merck says methaemoglobinaemia turns the gums and other mucous membranes brown or muddy.

What an owner may see:

  • gums or other mucous membranes that look brown or muddy, or bluish
  • tiredness and weakness
  • vomiting
  • swelling of the face or paws

Pet Poison Helpline lists the broader picture as stomach upset, blood abnormalities and liver failure. The ASPCA lists vomiting, heavy drooling, lethargy, breathing problems and discoloured gums for cats that have swallowed paracetamol or aspirin. Merck says methaemoglobinaemia and liver injury characterise the poisoning in cats, and that kidney injury is also possible.

Because the signs take a few hours to develop, a cat can look normal at first. That is why “wait and watch” is the wrong plan.

Dogs. Merck says jaundice, liver injury and liver cell death are more common with paracetamol poisoning in dogs than in cats. Dogs can also show loss of appetite, belly pain, vomiting and tremors, and some develop sudden dry eye. Merck also notes that poisoning can occur at lower amounts when exposure is repeated.

Where paracetamol hides in an Indian home

The names on the strip hide the drug. We checked these brands against the manufacturer’s leaflet or an Indian pharmacy listing on 16 October 2026:

  • Dolo 650 (Micro Labs): paracetamol
  • Crocin 650 and Crocin Advance: paracetamol
  • Crocin Pain Relief: paracetamol and caffeine
  • Calpol (GSK): paracetamol, as tablets, suspension and paediatric drops

It also sits inside combination products, where the label does not say “paracetamol” in big letters:

  • Combiflam (Sanofi): ibuprofen and paracetamol
  • Saridon (Bayer): paracetamol and caffeine (the same listing also mentions propyphenazone elsewhere on the page, so read your pack)
  • Sinarest New (Centaur): paracetamol, phenylephrine and chlorpheniramine
  • D’Cold Total (Reckitt): paracetamol, caffeine and phenylephrine
  • Ultracet (Janssen): tramadol and paracetamol

The Merck Veterinary Manual notes that acetaminophen and some anti-inflammatory painkillers are present in many cough and cold products. Formulations change, and one brand name can cover several products, so read the ingredient list on your own pack. Caffeine in these products is a second problem: Pet Poison Helpline says dogs and cats appear more sensitive to caffeine than people.

We list the ingredients of these brands, and more, on our page Human medicines that are dangerous to pets. It deliberately gives no doses for any medicine, and neither does this article. No amount of human paracetamol can be called safe for a cat.

The same enzyme gap affects other medicines

Paracetamol is the best-known example, but the cat’s limited ability to clear many drugs shows up again and again in the veterinary sources:

  • Aspirin. Merck says cats are very susceptible because they are deficient in glucuronyl transferase and excrete aspirin slowly.
  • Ibuprofen and naproxen. Merck says cats are especially susceptible to ibuprofen because of limited glucuronide conjugating capacity, and may be more susceptible to naproxen for the same reason.
  • Sleeping and anxiety tablets. Merck says benzodiazepines are cleared mostly by glucuronidation, so cats can be more susceptible, and some cats have developed potentially fatal liver failure after several days of oral diazepam.
  • Essential oils. Merck says cats are especially at risk because they are deficient in glucuronyl transferase and are very sensitive to phenolic compounds.
  • Permethrin. A published series of 42 cats found that 41 had a permethrin spot-on made for dogs applied, and that in most cases the product had been applied directly to the cat. The paper’s introduction notes that a deficiency of hepatic glucuronosyltransferase has been suggested as a possible explanation for cats’ sensitivity.

The practical rule that follows is simple. Never give a cat a human medicine, and never give a cat a dog’s medicine, unless a vet who has examined that cat tells you to.

What your vet will do

What happens depends on the product, how long ago it was swallowed and how your cat is. From the Merck Veterinary Manual, treatment of paracetamol poisoning generally involves:

  • Early decontamination. When it is done early, that can mean inducing vomiting in the clinic, then activated charcoal. The ASPCA warns against doing this at home, and Merck says vomiting is useful when it is done early.
  • An antidote. Merck describes N-acetylcysteine as a potential antidote. Methylene blue and ascorbic acid may lower the methaemoglobin level.
  • Supportive care. Fluids by drip, correction of electrolytes, anti-sickness medicine, and blood transfusions when needed.
  • Monitoring. Methaemoglobin, Heinz-body anaemia, red cell breakdown and liver enzymes are checked.

Because decontamination helps most when it is done early, phone at once. The same rule applies to dogs: never give a human fever or pain tablet, and call a vet if one has been swallowed.

This article is general education. It is not veterinary advice and cannot examine your cat.

Sources

General education, not veterinary advice for your animal. See the disclaimer and how articles are checked in the editorial policy.

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