Why is chocolate bad for dogs?

There is a toxic ingredient in chocolate called theobromine (a bit like caffeine) which is poisonous to dogs. It’s naturally found in cacao beans. The amount of theobromine typically depends on the type of chocolate. Darker, purer varieties tend to have the highest levels but it’s also found in milk chocolate. The bottom line is dogs and chocolate don’t mix.

What to do if your dog eats chocolate?

Urgent treatment may be needed if your dog has eaten chocolate so please contact your vet as soon as possible for advice or, out of hours, your nearest Vets Now pet emergency clinic or Vets Now 24/7 hospital by entering your address or postcode below.

It will assist your vet if you can tell them how much chocolate your dog ate, what type of it was — wrappers can be very helpful — and when your dog ate it. This will enable them to work out whether your dog has eaten a toxic dose and what treatment they’re likely to need.

It will also help if you can provide an estimate of how heavy your dog is (click here to find out).

How much chocolate can a dog eat?

Can dogs eat chocolate in small quantities is a question owners often ask, but our advice is not to give any to your dog. However, if they have managed to eat some these are some guidelines you need to be aware of:

Firstly, you need to know how heavy your dog is (click here to find out). Theobromine doses in the region of 100-150 milligrams per kilogram of bodyweight are toxic to dogs, so if you have a Labrador weighing 30kg, as little as 3000mg of theobromine could be fatal.

You’ll find 3000mg of theobromine in one 500 gram bar of dark or 170 grams of baking chocolate, which is often less than a single bar. However, for West Highland Terriers weighing just 10kg these amounts should be reduced by two-thirds.

You can use our interactive dog chocolate calculator below to find out if your dog has eaten a poisonous amount.


What happens if a dog eats chocolate?

Chocolate poisoning mainly affects the heart, central nervous system and kidneys. Dog ate chocolate symptoms usually occur between four and 24 hours after your dog has eaten chocolate.

The effect and signs of chocolate poisoning in dogs depends on the amount eaten and the size of the breed. For example, a Labrador-sized dog that’s eaten 200g of milk chocolate is likely to have a stomach upset such as vomiting and diarrhoea. At 500g, it’s likely that cardiovascular problems and increased heart rate will be seen. Eating 750g may result in seizures.

It can be hard to tell exactly how much chocolate your dog has eaten and the amount of caffeine and theobromine will vary due to growing conditions, cocoa bean sources and variety. It’s always best to err on the side of caution and contact your vet for advice if you’re concerned.

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Chocolate and dogs treatment

There is no antidote to theobromine. In most cases, your vet will make your dog vomit.  They may wash out the stomach and feed activated charcoal which will absorb any theobromine left in the intestine. Other treatments will depend on the signs your dog is showing.

They may also need intravenous fluids (a drip), medication to control heart rate, blood pressure and seizure activity. With prompt intervention and treatment, the prognosis for a poisoned dog is usually good — even in those who have eaten large amounts.

Image of chocolate for Vets Now article on my dog ate chocolate
Dark chocolate has high levels of theobromine