Emergency? Call now - do not wait for symptoms.
Is Acetaminophen (Paracetamol / Tylenol) toxic to dogs or cats?
Category: Medication | Last reviewed: April 2026
Quick verdict
Dogs
TOXICCats
EMERGENCYAcetaminophen (Paracetamol / Tylenol) and dogs
Dogs can tolerate very small amounts of acetaminophen (it is occasionally used in veterinary medicine), but the margin between a safe dose and a toxic dose is narrow. A single regular human tablet is dangerous for a small dog. Liver damage and methaemoglobinaemia are the primary concerns.
Onset
1-4 hours
Symptoms
- - vomiting
- - lethargy
- - abdominal pain
- - swollen face or limbs
- - dark urine
- - liver damage
What to do now
Contact ASPCA Poison Control (888-426-4435) or your vet immediately. Bring the packaging if possible.
Toxicity is dose-dependent. Your dog's weight and the quantity consumed are both important - include these when you call poison control.
Acetaminophen (Paracetamol / Tylenol) and cats
Acetaminophen is catastrophically toxic to cats. A single regular-strength tablet (500mg) is a potentially fatal dose for an average cat. Cats lack the liver enzyme (glucuronyl transferase) needed to metabolise acetaminophen safely, causing rapid accumulation of toxic metabolites. Methemoglobin builds up, starving tissues of oxygen. This is one of the most serious veterinary toxicology emergencies.
Onset
30 minutes to 4 hours
Symptoms
- - lethargy
- - weakness
- - brown or blue-tinged gums
- - facial swelling
- - swollen paws
- - difficulty breathing
- - liver failure
- - death
What to do now
CRITICAL EMERGENCY. Rush to an emergency vet immediately - minutes matter. Do not induce vomiting. Call ASPCA Poison Control (888-426-4435) while in transit.
Data sources
- - ASPCA Animal Poison Control
- - Feline acetaminophen toxicosis - JAVMA
- - VCA Animal Hospital
- - Pet Poison Helpline
Last reviewed: April 2026
Data error? Email data@treatortoxic.com with a source reference.