My dog ate chocolate - how worried should I be?
Chocolate is toxic to dogs because of theobromine, and the danger depends on your dog's size, the type of chocolate and how much they ate. Enter the details for an estimated dose and risk level - then use it to talk to your vet, not instead of it.
Chocolate poisoning is dose-dependent - a square of milk chocolate rarely harms a big dog, while the same amount of dark chocolate can seriously affect a small one.
What to watch for: vomiting, diarrhoea, restlessness, heavy panting, a racing heart, tremors or seizures - usually within 6 to 12 hours. Signs can be delayed, so keep watching through the day.
This is an estimate to help you gauge urgency, not a diagnosis. Theobromine content varies between products, and dogs differ in sensitivity - so when in doubt, call your vet or a poison-control line with the packaging in hand. They may advise inducing vomiting if it was recent, and early action is always safest. Never wait for symptoms if a large or dark-chocolate dose is involved.
Where the figures come from: the Merck Veterinary Manual's chapter on chocolate toxicosis. It gives the content of methylxanthines (theobromine plus caffeine) as 2.3 mg per gram for milk chocolate, 5.3-5.6 for dark, 15.5 for unsweetened baking chocolate and 28.5 for dry cocoa powder, and the doses for dogs as about 20 mg/kg for mild signs, 40-50 mg/kg for effects on the heart and 60 mg/kg or more for seizures. For white chocolate the calculator deliberately assumes more than the manual's figure. Read on 10 October 2026.