Why Is Chocolate So Bad For Dogs? What Are The Real Reasons?

why is chocolate bad for dogs
© Armadillo Stock/Shutterstock.com

Written by Sharon Parry

Updated: January 24, 2023

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It’s a delicious sweet treat that we humans love. We even give chocolate as a gift at special times of the year. Yet, for our dogs, it is a highly toxic and dangerous substance. So, why is chocolate bad for dogs? Here we explain the science behind this household hazard and give you some tips on how to stop your pooch from getting at your chocolate stash!

Why Is Chocolate Bad for Dogs?

There are two ingredients in chocolate that make it bad for dogs. They are called theobromine and caffeine. Both of these chemicals are diuretics (they make the body lose water), heart stimulants (they speed up the heart) blood vessel dilators (they open up the blood vessels), and smooth muscle relaxants.

They have the same effect on the human body. The difference is that our bodies can break down these chemicals quickly and get rid of them. A dog’s body is really bad at breaking them down, so they hang around in the bloodstream for days and this causes a huge challenge to the organs.

Also, some sugar-free chocolate contains an artificial sweetener called xylitol. This can make a dog’s blood sugar level drop so low that it causes liver failure.   

How Much Chocolate Is Toxic For Dogs?

This is where things can get a little confusing. You may have heard tales from your friends claiming that their dog ate some chocolate and was perfectly fine. This is entirely possible. The severity of a dog’s illness will depend on the type of chocolate that they ate, the quantity of chocolate ingested and the size and age of the dog. Experts also suspect that some dogs are genetically more likely to suffer serious illness after eating chocolate than others.

As you would expect, larger dogs can handle more chocolate than smaller dogs. Also, dogs with pre-existing health conditions can be more vulnerable. There are several online toxicity calculators that can help you work out how the chocolate will affect your dog. However, there is no substitute for direct consultation with your vet.

We’ve put together a handy table of some common chocolate products and the amount of theobromine they contain.

Type of chocolateApproximate Theobromine content
Cocoa20.3 mg/g
Baking chocolate13 mg/g
Dark confectionary chocolate4.41 mg/g
Milk confectionary chocolate1.88 mg/g
Chocolate cupcakes1.5 mg/g
Chocolate ice cream0.62 mg/g
White chocolateVery small amounts

Cocoa shell mulch is very high in theobromine and should not be used in your garden if you have a dog.

Clinical Signs of Chocolate Poisoning in Dogs

Dogs usually become unwell within 6 to 12 hours of eating chocolate and the symptoms can last for up to three days. It usually starts with your dog vomiting but here is a complete list of the possible signs:

  • Vomiting (being sick)
  • Diarrhea (frequent and liquid poops)
  • Stomach pain
  • Excessive drooling
  • Loss of co-ordination
  • Appearing restless (theobromine is a stimulant)
  • Panting
  • Peeing more often
  • Increased thirst
  • Fast heartbeat
  • Fast breathing rate
  • Muscle tremors – shaking
  • Seizures
  • Aspiration pneumonia from inhaling vomit
  • Eventual collapse with heart failure

Sadly, some dogs die after eating chocolate. Senior dogs and those with existing heart problems are most likely to have a poor outcome.

How to Prevent Your Dog From Eating Chocolate

Dogs don’t understand that chocolate is bad for them and will gobble it up if they get the chance. So, it is your responsibility to prevent this from happening. Here are some hacks to keep your dog safe.

Identify the Riskiest Times

There are some times of the year when we tend to have more chocolate in our homes. Christmas, Easter, and birthdays are typical examples. These are also the times when there are more people in the home, things are a little chaotic and you are not watching the dog so closely. Dogs are opportunists and this is exactly when they are most likely to eat something that they should not. Dogs are four times more likely to end up at the vet with chocolate poisoning at Christmas than at any other time of the year!

Try to be vigilant and place advent calendars, easter eggs, and chocolate coins out of reach of the dog. Easter egg hunts can be especially risky because the dog is always going to reach the chocolates before the kids do – their amazing sense of smell gives them a head start! Lock your dog away whilst the hunt is on and count all the eggs so you can be sure they have all been found before letting your dog out.

Don’t Rely on Wrappers

Wrappers, advent calendar boxes, easter egg boxes, and gift wrapping will NOT keep a dog out. Wrapped chocolate gifts should not be left under the tree at Christmas.  Coins cannot be hung from the low branches of the Christmas tree either.

The wrappers could actually present even more of a danger. They are not usually poisonous, but they can cause a blockage in your dog’s intestine. You could always prevent your dog from getting access to the tree using a dog barrier.

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Store Chocolate Where Dogs Cannot Reach

This may seem obvious, but you will be surprised where a determined dog can get to. Dogs have stolen chocolate from countertops, pockets, handbags, and from inside cars. Make sure that everyone in your home is aware that your dog cannot have chocolate and gets in the habit of hiding it away.

Crate Train Your Dog

If you are having issues with your dog pinching food from countertops or even out of children’s hands, it is time to crate train them. When your pooch is not being closely supervised, it will be safely locked away in its crate. You can use a Kong or similar interactive toy to keep them amused.

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Teach The ‘Leave it’ Command

This is an often-overlooked command yet it can literally save a dog’s life. Using a low-value treat (e.g. kibble) and a high-value treat, teach your dog that if they obey the ‘leave it’ command they get a fabulous treat. There are plenty of training guides that will work you through this step by step.

Be Vigilant on Walks

Dogs that scavenge in gutters often find discarded chocolate bars and have swallowed them before you have a chance to intervene. Eating things from gutters and sidewalks is not a good habit for a dog to get into. You may need to use a head halter to control their head whilst you are on walks until they learn the ‘leave it’ command.

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What to Do if Your Dog Eats Chocolate

If your dog eats chocolate, you must contact your vet right away. Your vet will need to work out how serious this situation is and to do that, they will need some vital information from you. Have this information ready before you make the call.

  • Your dog’s age and breed
  • Your dog’s weight
  • The type of chocolate that your dog has eaten
  • The ingredients (you should be able to get this from the packaging)
  • How long ago the chocolate was eaten
  • If your dog also swallowed the wrapper
  • Any symptoms that your dog is currently experiencing

You will probably need to then take your dog to veterinary surgery right away. If your dog is already experiencing symptoms, head off to the vet immediately and have someone call ahead so they know that you are on the way. Do NOT try to make your dog vomit yourself as this can make the situation worse.

The treatment that the vet gives your dog will depend on your dog’s symptoms, their weight, and how much chocolate they have ingested. In mild cases where a large dog has ingested a tiny amount of chocolate, they may simply monitor them. Vets may also give your dog something to make them vomit – this needs to be done within two hours of eating the chocolate. They can also give activated charcoal, which soaks up the toxins in the intestines so that the body can expel them without absorbing them.

In severe poisonings, your dog may need IV fluids and treatment for seizures. They may also need medication to control their heart rate.  In the recovery phase, your dog may need a special gastro-intestinal support food that is gentle on their stomach.

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About the Author

Dr Sharon Parry is a writer at A-Z animals where her primary focus is on dogs, animal behavior, and research. Sharon holds a PhD from Leeds University, UK which she earned in 1998 and has been working as a science writer for the last 15 years. A resident of Wales, UK, Sharon loves taking care of her spaniel named Dexter and hiking around coastlines and mountains.

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