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.

All your dog and chocolate questions answered — click to open

1. Can dogs eat chocolate?

Our advice is not to give any to your dog, but if they have managed to eat some you need to know how heavy your dog is (click here to find out). You should then try to work out whether they have swallowed a toxic dose. Our chocolate calculator should help you.

2. Why is chocolate bad for dogs?

Chocolate contains a number of ingredients that are bad for dogs, including fat, sugar and caffeine. But the most toxic ingredient is theobromine, which is a bitter alkaloid of the cacao plant. Dogs aren’t able to break down, or metabolise, theobromine like humans can.

3. How much chocolate is dangerous to dogs?

It depends on the type of chocolate and the size of the dog but, as a rule, toxic effects in dogs occur at theobromine doses of 20 milligrams per kilogram of weight, with severe signs at 40-50 mg/kg and seizures at 60 mg/kg. Owners whose dogs have eaten 3.5g of dark chocolate for every 1kg they weigh, or 14g of milk chocolate for every kg they weigh, should consult their vet.

Image of dark chocolate for Vets Now article on chocolate dogs
Dark chocolate, baker’s chocolate and cocoa powder is typically the most toxic for dogs

4. How much chocolate can kill a dog?

While chocolate can make dogs ill, it’s rarely fatal. According to the Veterinary Poisons Information Service, out of 1,000 chocolate toxicity cases it recorded on its database, only five dogs died. Concerns have been raised, however, that many chocolate toxicity cases go unreported.

5. Is chocolate powder dangerous to dogs?

Dry cocoa powder contains up to 26mg of theobromine per gram so is highly toxic to dogs. If you have a dog weighing 10kg, as little as a few grams of cocoa powder could potentially result in your dog suffering seizures.

6. My dog drank hot chocolate. Is it dangerous?

Popular versions of drinking chocolate tend to have similar, or lower, levels of theobromine to milk chocolate. That means a 10kg dog would need to ingest up to 130g of drinking chocolate to suffer toxic effects.

7. Are all dogs at risk from chocolate poisoning?

It’s believed there may be some sort of genetic susceptibility to theobromine poisoning in certain dogs. While some do not show any clinical signs after eating chocolate, others develop severe signs such as seizures and irregular heart rhythms.

8. What does chocolate do to dogs?

The toxic chemical in chocolate, theobromine, has been used in human medicine as a heart stimulant and a muscle relaxant. It’s also a diuretic, which means it makes you go to the toilet. On top of that it dilates blood vessels and can lead to potentially lethal over-stimulation of the heart. Dogs don’t process theobromine well and it can cause sickness, diarrhoea and kidney problems.

9. How to know if your dog ate chocolate?

If your dog has eaten a potentially dangerous amount of chocolate it’s likely he will start showing symptoms between four and 24 hours after ingestion. The most typical symptoms are sickness and diarrhoea, which may contain blood, as well as restlessness and hyperactivity, rapid breathing, muscle tension, incoordination, increased heart rate and seizures.

10. What to do if your dog eats chocolate?

If you discover your dog ate chocolate try to work out what type it was, how much they ate and when they ate it. Our chocolate toxicity calculator can help with this. Dark chocolate, baker’s chocolate and cocoa powder is typically the most toxic. If your dog has eaten a potentially toxic amount you should call your vet or, out of hours, your nearest Vets Now.

Chocolate ice cream can be toxic to dogs and also contains unhealthy ingredients such as sugar and fat

11. Can dogs eat white chocolate?

It’s highly unlikely your dog will suffer poisoning from eating white chocolate, unless they are very small or have consumed massive amounts. Of all the forms of chocolate, white contains the lowest amount of toxic theobromine. This is the case for all white chocolate products, including those which claim to contain cocoa solids. But bear in mind white chocolate is high in fat, buttermilk and sugar so may cause a stomach upset.

12. How much dark chocolate will kill a dog?

A good quality 500g bar of dark chocolate can contain as much as 4000 mg of theobromine. That’s more than enough to kill a 30kg dog such as a Labrador. But even lower quality grades of dark chocolate are dangerous to dogs. For example, a 500g bar with 45 to 59% cacao solids can contain up to 2500mg of theobromine.

13. What to give a dog that ate chocolate?

Never resort to home remedies to treat dogs for chocolate poisoning. Instead, find out how much they’ve eaten, what type of chocolate it was, and what weight your dog is. This way you can work out whether the dose is toxic enough to warrant urgent veterinary treatment.

14. What to do if your dog eats a dangerous amount of chocolate?

Call your vet for advice or, out of hours, your nearest Vets Now. It will assist your vet if you can tell them how much chocolate your dog ate, what type 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.

15. How to treat a dog for chocolate poisoning?

There’s no antidote to theobromine or chocolate poisoning. In most cases, if they ate the chocolate within a few hours, your vet will make your dog vomit. They may also wash out the stomach and feed them activated charcoal. Other treatments will depend on the signs your dog is showing and can often include intravenous fluids. The prognosis for a poisoned dog who is treated quickly is usually good.

16. Can dogs eat chocolate cake?

In short, no. Chocolate cake contains a number of ingredients that are bad for dogs — including cocoa powder and sugar. Cocoa powder, in particular, is particularly toxic as it contains high levels of theobromine.

17. Is chocolate ice cream bad for dogs?

Chocolate ice cream can contain theobromine. It is also full of unhealthy ingredients such as sugar and fat which are bad for dogs. In addition, most dogs are lactose intolerant, so drinking foods high in milk or cream may result in a stomach upset or, even worse, severe clinical signs.

Also on this topic

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