Why is chocolate bad for dogs? And how much chocolate is poisonous to dogs?

Written by Napo HQ
Reviewed by Dr Louisa Lane
7th Jul 2022
6 mins read
Most of us know that chocolate is toxic to dogs. That's because it contains the chemical “theobromine”. Theobromine is toxic and causes problems including increased heart rate, breathing, and blood pressure.
Never give your dog chocolate or any food or drink that contains chocolate or cocoa. Avoid using cocoa mulch in your garden.
If your dog eats any chocolate, contact your vet. Try to tell the vet what type of chocolate your dog ate, how much they ate, and when they ate it.
Many owners know that chocolate is toxic to dogs and that you should never feed your dog chocolate.
However, dogs will eat almost anything, and accidents can happen.
Dogs eating something they shouldn’t is one of the most common claims here at Napo and can cost between £1200-2000 to treat. Luckily, insurance is there to help pay for unexpected vet bills.
To coincide with World Chocolate Day, we're going to tell you all you need to know about chocolate and dogs. We’ll explain why chocolate is dangerous for our furry friends, the symptoms of chocolate poisoning, and what to do if your dog eats chocolate.

Why is chocolate bad for dogs?

Chocolate is toxic to a lot of animals, including dogs. This is because chocolate naturally contains two similar chemicals called “theobromine” and “caffeine” which are both toxic to dogs.
In addition, a dog’s body can’t break down theobromine or caffeine efficiently during digestion, and both chemicals also have long half-lives.
That means instead of the body breaking it down during digestion, the chemicals stays in their bloodstream for a longer time. So it continues to make your dog sick.
Theobromine and caffeine are both stimulants. They cause increased breathing rate, elevated heart rate, and high blood pressure. They are also muscle relaxants and diuretics. That means your dog’s body is repeatedly subjected to all these effects, which causes their sickness.

Other ingredients can make your dog sick too

Some chocolates can contain other ingredients that are toxic to dogs, including alcohol, nuts, and raisins.
Another reason why chocolate is bad for dogs is because it contains a lot of sugar and fat. If your pet has too much sugar or fat in their diet it can contribute to various health conditions, such as obesity and diabetes.
The high levels of fat in foods like chocolate can also put your pet at risk of a serious condition called pancreatitis, which can be fatal in some cases.

Will chocolate kill dogs if they eat it?

Eating chocolate can put your dog’s life at risk. However, fatal cases of chocolate poisoning in dogs are rare.
However, eating chocolate could be a medical emergency depending on the size and age of your dog, and the type and amount of chocolate that they have eaten.
Small dogs, young puppies, old dogs, and dogs with health conditions are more at risk of serious illness or death if they eat something toxic, like chocolate.

What are dangerous doses of chocolate for dogs?

Dogs show symptoms of illness after eating as little as 20mg of theobromine per kilogram of bodyweight.
That means how much chocolate is poisonous to dogs depends on their size. A huge dog like a Great Dane is at lower risk of chocolate poisoning compared to a tiny dog like a Chihuahua.
The more theobromine your dog eats, the more severe their symptoms and illness.
If they eat more than 60mg/kg of theobromine, they will likely suffer neurological symptoms such as seizures.
100mg/kg of theobromine becomes a potentially fatal dose.

What type of chocolate is the most dangerous for dogs?

The amount of theobromine in chocolate varies depending on the type of chocolate.
White chocolate contains very little, about 0.2mg/g of chocolate. Meanwhile, milk chocolate is around 2mg/g.
Baking chocolate and dark chocolate are the most dangerous and contain around 20mg/g of theobromine.
That means if your dog eats white chocolate, they’re less likely to be seriously ill. However, eating just a tiny piece of dark chocolate could cause significant illness or put your pet’s life at risk.

How much chocolate is poisonous to dogs?

As explained above, how much chocolate is poisonous to dogs depends on the type of chocolate and the amount eaten.
One square of chocolate is around 4-5g. A piece of milk chocolate would have around 10mg of theobromine. But a square of dark chocolate contains 80-100mg of theobromine.
Although that's a lot of theobromine, remember that how much chocolate is poisonous to dogs also depends on the dog's size. If a 1.8kg Yorkshire Terrier ate two squares of dark chocolate, that can put their life at risk. On the other hand, if a large 30kg Labrador ate those two pieces of dark chocolate, they'd be unwell and need veterinary treatment, but it's unlikely to be fatal.
The safest thing to do is to make sure your dog never eats chocolate. And if they ever do, remember how much they ate, what type of chocolate it was, and when they ate it. This will help your vet when they treat your pup.

Signs of chocolate poisoning in dogs

It can take 6 to 12 hours before your dog shows any sign of illness after eating chocolate. Symptoms of chocolate poisoning in dogs include:
  • Restlessness
  • Agitation
  • Loss of appetite
  • Vomiting
  • Diarrhoea
  • Increased thirst (Polydipsia)
  • Hyperactivity
  • Stomach pain
  • Increased urination
  • Fever
  • Loss of coordination (Ataxia)
  • Rapid heart rate
  • High blood pressure
  • Blue tinge to the skin (Cyanosis)
  • Tremors
  • Cardiac arrest
  • Seizures

What should you do if your dog eats chocolate?

If your dog eats chocolate you must call your vet as soon as possible.
If you can, tell them what kind of chocolate your dog ate, how much they ate, and when they ate it. You should also tell them the size and age of your dog, as this affects their metabolism and tolerance of toxins.
make your dog vomit. Trying to induce vomiting, especially with products like hydrogen peroxide, will do more harm than good.
You'll probably be told to take your dog to the vet surgery as soon as possible, if the vet is concerned with the type or amount of chocolate eaten. Your pet will be given supportive treatment to combat their symptoms and help their body get rid of any toxins.

Treatment for chocolate poisoning in dogs

How your dog is treated will depend on their symptoms, the type of chocolate they ate, how much they ate, and when they ate it.
If your dog ate chocolate recently, your vet may induce vomiting to get as much out of their stomach as possible. Your dog might then be fed activated charcoal, or sent home with some to use later. Activated charcoal binds with toxins in their digestive system and prevents them from being absorbed into the body.
feed your dog any DIY charcoal at home as you may make your dog sicker. Activated charcoal is specially made and prescribed by a vet.
There is no “antidote” to chocolate poisoning. Treatment is supportive, which means it combats symptoms and supports your dog’s body to aid recovery.

Supportive treatments for chocolate poisoning in dogs

Supportive treatment for chocolate poisoning in dogs often involves IV fluids, which help to promote theobromine extraction through the liver.
Your dog might also be given further medication depending on their symptoms. For example, some dogs may receive sedatives to calm them and prevent restlessness. Other dogs may be given medication to control seizures.
After your dog is discharged, you’ll need to keep an eye on them for a few days. If they show any further signs of sickness, you’ll need to contact your vet.

How to prevent chocolate poisoning in dogs

Chocolate poisoning in dogs is entirely preventable, by making sure your dog can’t eat chocolate or any food or drink products that contain cocoa.
Consider keeping your chocolate sweets and biscuits in a container that your dog can’t open, and keep the container securely in your cupboard.
Make sure everyone in your home, including children, knows that they should never feed your dog chocolate, or anything containing chocolate. They should also never leave chocolate products lying around where your dog could eat them.
Additionally, make sure you don’t use cocoa mulch when you’re gardening. This by-product from the chocolate industry might be great for fertilising your garden, but it can be a disaster for your furry friends. It still contains theobromine, so your dog could become sick if they eat any.

Final thoughts

Because how much chocolate is poisonous to dogs depends on the size, age, and health of your dog, as well as the type and amount of chocolate, it's always safest to avoid giving your dog any chocolate at all.
To avoid preventable illness in your pet, never feed them any food or drink that contains chocolate.
Keep all chocolate products out of paws' reach. Take extra care to keep chocolate out of reach during the holidays, like Christmas and Easter, when more sweets are in the house and chocolate poisoning becomes more common.
If your dog does manage to eat some chocolate, call your vet straight away.

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