Why is chocolate dangerous for dogs and cats?
Chocolate contains theobromine and a small amount of caffeine — two methylxanthines that dogs and cats metabolise very slowly. They build up in the bloodstream, overstimulate the heart and nervous system, and in high doses cause seizures or heart arrhythmia.
Cats are roughly 1.3× more sensitive to theobromine than dogs, and dark chocolate, baking chocolate and cocoa powder contain far more theobromine than milk or white chocolate.
About the dose levels
Reference dose bands for dogs: <15 mg/kg low risk · 15–25 mg/kg watch and call · 25–40 mg/kg see a vet now · >40 mg/kg emergency. Symptoms usually appear within 6–12 hours.
Reference dose bands for dogs: <15 mg/kg low risk · 15–25 mg/kg watch and call · 25–40 mg/kg see a vet now · >40 mg/kg emergency. Symptoms usually appear within 6–12 hours.
Symptoms of chocolate poisoning
- Vomiting, diarrhoea, restlessness, hyperactivity
- Increased thirst, urination and panting
- Racing heart, tremors, muscle twitching
- Severe cases: seizures, collapse, heart arrhythmia
What to do right now
- Stay calm and record — the exact type of chocolate, amount, and your pet’s weight.
- Do NOT induce vomiting unless your vet tells you to.
- Call your vet or a poison line and keep the wrapper or box handy.
- Follow their advice — treatment may include decontamination, activated charcoal, IV fluids and monitoring.
If your pet is already showing symptoms, don’t wait for a calculator result — call your vet or the ASPCA Poison Control center (888) 426-4435 immediately.
Sources & further reading
- ASPCA Animal Poison Control — pet poison database & dosage references
- Pet Poison Helpline — toxicology triage guidelines
- Merck Veterinary Manual — toxicology monographs
- Vets Now (UK) — emergency toxicosis guidance