My dog ate chocolate: how dangerous is it?
The dose per kilo from the Merck Veterinary Manual, and the sheet to read to your vet. The answer is never “it’s nothing”.
Cats: we don’t calculate anything. Call your vet right away.
Why chocolate is dangerous
Chocolate contains theobromine and caffeine (methylxanthines). Dogs process them slowly, so they build up. The Merck Veterinary Manual lists how much there is in each type: cocoa powder 28.5 mg per gram, baking chocolate 15.5, dark 5.3–5.6, milk 2.3, white 0.04 (almost none). With the cocoa percentage on the label, multiply 15.5 by the percentage: a 70% bar has about 10.9 mg per gram.
The manual’s thresholds for dogs: 20 mg/kg mild signs (vomiting, diarrhea, thirst), 40–50 mg/kg heart effects, 60 mg/kg and over seizures. Sensitivity varies from dog to dog: that’s why this tool always tells you to call.
Sources
- Merck Veterinary Manual, “Chocolate Toxicosis in Animals” (checked on October 6, 2026)