Is Tylenol (Acetaminophen) Toxic to Dogs and Cats?
Acetaminophen (sold as Tylenol, Paracetamol) is extremely toxic to cats and can be dangerous to dogs at moderate doses. Cats lack the liver enzyme (glucuronyl transferase) needed to metabolize acetaminophen, making even a single regular-strength tablet potentially fatal.
What Makes Acetaminophen (Tylenol) Dangerous to Pets?
Acetaminophen (sold as Tylenol, Paracetamol) is extremely toxic to cats and can be dangerous to dogs at moderate doses. Cats lack the liver enzyme (glucuronyl transferase) needed to metabolize acetaminophen, making even a single regular-strength tablet potentially fatal. In dogs, acetaminophen causes liver damage at higher doses. This is one of the most common well-intentioned poisonings, as owners try to treat their pet's pain with human medication.
Toxic Agent
Acetaminophen (paracetamol, N-acetyl-p-aminophenol)
Common Sources
- •Tylenol and generic acetaminophen tablets
- •Extra Strength Tylenol (500 mg per tablet)
- •Cold/flu combination products (NyQuil, DayQuil, Theraflu)
- •Prescription pain medications containing acetaminophen (Vicodin, Percocet)
- •Children's liquid Tylenol
Symptoms of Acetaminophen (Tylenol) Poisoning in Dogs & Cats
Mild Symptoms
- ▸Vomiting and loss of appetite
- ▸Lethargy and depression
- ▸Facial or paw swelling (cats)
Moderate Symptoms
- ▸Brown or blue-tinged gums (methemoglobinemia)
- ▸Difficulty breathing and rapid breathing
- ▸Dark brown or chocolate-colored urine
Severe / Emergency
- ▸Liver failure (jaundice — yellowing of eyes/gums)
- ▸Severe anemia and methemoglobinemia
- ▸Death within 18-36 hours (cats)
What to Do If Your Pet Is Exposed to Acetaminophen (Tylenol)
- 1
Determine the strength (mg) and number of tablets ingested.
- 2
NOTE: If the product also contains other drugs (e.g., pseudoephedrine, codeine), report those too.
- 3
Do NOT try to treat at home — cats especially need immediate emergency care.
- 4
Use VetGeni's free toxin checker for a risk assessment.
- 5
Contact your veterinarian or emergency clinic immediately.
When to See the Vet
Immediately for any acetaminophen ingestion in cats. For dogs, seek care if ingestion exceeds 75 mg/kg. Cats can die from a single 325 mg tablet.
Prognosis
Cats: Guarded to poor without immediate treatment with N-acetylcysteine (NAC). Dogs: Good with prompt treatment for moderate doses. Delayed treatment significantly worsens outcomes for both species.
Check Acetaminophen (Tylenol) Toxicity for Your Pet
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Use the Free Toxin Checker ↓Is this toxic to my pet?
Find out if a substance is toxic to your pet and what to do. Fast, free triage guidance for dogs and cats.
Is it Toxic?
Instant triage guidance for potential poisonings.
What you'll get
- Risk level and urgency guidance in plain language
- Expected symptoms to watch for over the next hours
- Next steps your vet may recommend
If symptoms are severe
Contact your veterinarian or an emergency animal hospital immediately.
Have this ready
- Substance and estimated amount
- Pet weight and species
- Time since ingestion
- Current symptoms, if any
Frequently Asked Questions
- Can one Tylenol kill a cat?
- Yes. A single regular-strength Tylenol (325 mg) can be fatal to a cat. Cats lack the liver enzyme needed to metabolize acetaminophen safely. Half a tablet can cause severe methemoglobinemia (oxygen deprivation). Never give Tylenol to cats under any circumstances.
- Is acetaminophen safe for dogs?
- Acetaminophen is not safe for dogs without specific veterinary guidance. While some veterinarians may occasionally prescribe it at very low doses, the margin of safety is narrow. Liver failure can occur at doses above 75-100 mg/kg. Never give Tylenol to your dog without consulting a vet.
- What is the antidote for acetaminophen poisoning in pets?
- N-acetylcysteine (NAC) is the primary antidote and works by replenishing glutathione, which helps the liver detoxify acetaminophen. It is most effective when given within 8-10 hours of ingestion. Additional treatments include vitamin C, SAMe, and supportive care.
Emergency? Call Poison Control
If your pet is showing severe symptoms, call immediately:
Veterinary Professionals: Get Full Toxicology Reports
VetGeni Pro provides dose-specific toxicology reports with treatment protocols, drug calculations, and Wiley-referenced clinical guidance.
Reviewed by Dr. Christopher Tiller, DVM — Emergency Veterinarian & VetGeni Founder. This information is for educational purposes and does not replace professional veterinary care. Always consult a veterinarian for specific medical advice.