If your pet ate acetaminophen, call your veterinarian or an animal poison control center now. Use the acetaminophen calculator to estimate the dose for your dog or cat.
Enter weight and amount to get an urgency level and next steps.
What to do right now
- Move your pet away from the source and pick up anything left over.
- Find the packaging, label, or plant so you know exactly what was eaten and how much.
- Note your pet's weight and the time it happened.
- Call your veterinarian or an animal poison control center. Do this even if your pet seems normal.
- Do not make your pet vomit unless a professional tells you to.
- Follow the advice you are given, and bring the packaging to the clinic.
Why acetaminophen is dangerous
Cats lack the liver enzymes needed to break acetaminophen down safely. Toxic byproducts build up and damage red blood cells, turning hemoglobin into a form that cannot carry oxygen. This is called methemoglobinemia. Signs have been reported in cats at doses as low as 10 mg per kg, which is less than a quarter of a regular tablet for an average cat.
In dogs, clinical signs are generally not seen below about 100 mg per kg, and red blood cell damage has been reported above about 200 mg per kg. Repeated doses can cause toxicity at lower amounts, and dogs are more likely than cats to develop liver injury.
Symptoms to watch for
- Brown or muddy-colored gums
- Fast or labored breathing
- Swelling of the face or paws
- Weakness and lethargy
- Vomiting and loss of appetite
- Yellow gums or eyes later on
Timeline: when signs appear
In cats, changes in the blood can begin within a few hours. In dogs, liver injury usually develops over 12 to 36 hours. Severe cases can progress to collapse within 24 to 72 hours without treatment.
Go straight to an emergency vet if
- The pet is a cat, regardless of amount
- Your pet has brown or muddy-colored gums, trouble breathing, a swollen face or paws, or is weak
- The estimated dose for your dog is in the Emergency range
- Poison control or your vet has told you to come in
What the vet will do
There is an antidote, acetylcysteine, which works best when started early. The vet may also induce vomiting, give activated charcoal, and provide oxygen, IV fluids, and other supportive care.
Bloodwork tracks the red blood cells and liver over several days. Some pets need a blood transfusion.
How to prevent it
- Never give acetaminophen to a cat, and never give it to a dog unless your vet prescribes a specific dose.
- Store all medicines in closed cabinets.
- Read cold, flu, and sleep aid labels for acetaminophen.
- Pick up dropped pills right away.
For a room-by-room list you can print, see the pet poison-proofing checklist.
Enter weight and amount to get an urgency level and next steps.
Frequently asked questions
How much Tylenol is toxic to a cat?
Any amount. Signs have been reported at 10 mg per kg, so even part of one tablet can be dangerous.
How much Tylenol is toxic to a dog?
Signs are generally not seen below about 100 mg per kg in a single dose, but repeated doses and liver disease lower that. Our calculator uses a conservative margin.
Can I give my dog Tylenol for pain?
Only if your veterinarian prescribes a specific dose. Never give it to a cat.
What are the first signs in a cat?
Brown or muddy gums, fast breathing, weakness, and swelling of the face or paws. Go to an emergency vet immediately.