Acetaminophen (Tylenol) Toxicity Calculator for Dogs
Merck Veterinary Manual reports clinical acetaminophen (Tylenol) toxicosis in dogs above 100 mg/kg and methemoglobinemia above 200 mg/kg, so a single 500 mg tablet is about 100 mg/kg for an 11 lb dog. (Merck Veterinary Manual; Pet Poison Helpline)
Acetaminophen toxicity calculator
Educational estimate from published toxicology references. Not veterinary advice. If in doubt, call your vet.
Risk level (example)
Call your vet
Estimated dose: 36.7 mg/kg
- Call your vet or a poison hotline for advice.
- Note the product, amount and time eaten; keep the packaging.
- Do not induce vomiting unless a veterinarian tells you to.
Emergency line
ASPCA APCC (888) 426-4435, fee may apply · Pet Poison Helpline (855) 764-7661, fee may apply
How thresholds are set: Merck Veterinary Manual reports clinical signs of acute acetaminophen toxicosis in dogs above 100 mg/kg and methemoglobinemia above 200 mg/kg. Because repeated doses and individual sensitivity can cause harm at lower amounts, any ingestion is treated as a reason to call, and from half the reported level (50 mg/kg) as a reason to call now.
Source: Merck Veterinary Manual — toxicoses from human analgesics; Pet Poison Helpline — acetaminophen
Educational estimate from published toxicology references. Not veterinary advice. If in doubt, call your vet.
Result tiers and what to do now
Call your vet — Below ~50 mg/kg
Call your vet or a poison hotline for advice; any ingestion warrants a call. (Pet Poison Helpline)
Call your vet now — ~50–100 mg/kg
Call right away; this is half the level where Merck reports clinical signs. (Merck Veterinary Manual)
Emergency — ≥ ~100 mg/kg
Go to the nearest emergency vet now; Merck reports signs above 100 mg/kg and methemoglobinemia above 200 mg/kg. (Merck Veterinary Manual)
Call for help
Call your vet or an emergency clinic. ASPCA Animal Poison Control Center (888) 426-4435 or Pet Poison Helpline (855) 764-7661 (fees may apply). Never induce vomiting without a vet's say-so.
Dose by dog weight
| Dog weight | 50 mg/kg (calculator's call-now level) | 100 mg/kg (signs, Merck) | 200 mg/kg (methemoglobinemia, Merck) |
|---|---|---|---|
| 5 lb (2.3 kg) | 0.2 tablets | 0.5 tablets | 0.9 tablets |
| 10 lb (4.5 kg) | 0.5 tablets | 0.9 tablets | 1.8 tablets |
| 20 lb (9.1 kg) | 0.9 tablets | 1.8 tablets | 3.6 tablets |
| 40 lb (18.1 kg) | 1.8 tablets | 3.6 tablets | 7.3 tablets |
| 80 lb (36.3 kg) | 3.6 tablets | 7.3 tablets | 15 tablets |
The 50 mg/kg column is this calculator's conservative half-of-reported level, not a published threshold. Repeated doses can cause harm at lower amounts. Published ranges are not safe allowances.
Frequently asked questions
How much Tylenol is toxic to a dog?
Merck Veterinary Manual reports clinical signs of acetaminophen toxicosis in dogs above 100 mg/kg and methemoglobinemia (blood unable to carry oxygen) above 200 mg/kg.
Is acetaminophen the same as Tylenol or paracetamol?
Yes. Tylenol is a brand of acetaminophen, also called paracetamol outside the US. Many cold and flu products contain it too — check the label.
What are the signs of acetaminophen poisoning?
Merck describes brown or muddy gums, fast breathing, facial or paw swelling, vomiting and liver injury. Call your vet before signs appear.
Should I make my dog vomit?
Never induce vomiting without a veterinarian's say-so. Call your vet or a poison hotline first.
Related calculators
Sources
Educational estimate from published toxicology references. Not veterinary advice. If in doubt, call your vet.