VeterUSA · Emergency triage
Did your cat eat acetaminophen?
Acetaminophen (Tylenol, paracetamol) is also hidden in many cold, flu, and sinus medicines. Enter what you know for a risk level and what to do next — but for cats, any amount is a reason to call.
Acetaminophen is one of the most dangerous human meds for cats. Cats can't safely process any amount, and a single regular tablet can be fatal. There's an antidote that works best given early — don't wait for symptoms.
Common acetaminophen strengths
- Regular Strength Tylenol, 1 tablet325 mg
- Extra Strength Tylenol, 1 tablet500 mg
- Children's chewable, 1 tablet80 mg
- Children's liquid, 1 tsp (5 mL)160 mg
- Cold/flu combo dose (NyQuil, etc.)325–650 mg
Acetaminophen hides in many combination products (cold, flu, sinus, sleep aids). If unsure, check the active-ingredients panel or call a poison line.
Both helplines are staffed 24/7 by veterinary toxicologists. A consultation fee may apply. If your cat has brown or blue-grey gums, is breathing hard, or is collapsing, skip the calculator and go to the nearest ER now.
How acetaminophen poisoning in cats works
Acetaminophen (the painkiller in Tylenol and many cold and flu products) is safe for people but uniquely dangerous to cats. Cats lack enough of a liver enzyme called glucuronyl transferase, so they can't safely break the drug down. Instead they form a toxic byproduct, NAPQI, that overwhelms the body's defenses — damaging red blood cells so the blood can't carry oxygen (methemoglobinemia), and injuring the liver.
When to worry
Veterinary references (Merck/MSD Veterinary Manual, ASPCA) place cats at risk of toxicity at doses as low as 10 mg per kg of body weight, with 50 mg/kg or more considered potentially lethal. For perspective, a single Regular Strength tablet (325 mg) is about 65 mg/kg for an average 11 lb (5 kg) cat — already in the dangerous range. There is no established safe dose for cats, so any known ingestion warrants a call.
Signs of acetaminophen poisoning in cats
Brown, blue, or grey gums; fast or labored breathing; swelling of the face or paws; drooling; vomiting; weakness; and sometimes brown-tinged urine — often within a few hours. Liver injury and jaundice (yellow gums/eyes) can follow over the next day or two.
Is there an antidote?
Yes — N-acetylcysteine (NAC), often with other supportive care, can be very effective, especially when started early. That's the single biggest reason not to "wait and see": the sooner a cat is treated, the better the outcome.
Is this calculator a substitute for a vet?
No. It gives a fast estimate using established veterinary thresholds so you can judge urgency. Because cats are so sensitive and because combination products vary, the result is only a guide — when in doubt, call a veterinarian or an animal poison control line right away rather than wait.