My Dog Ate A Dark Chocolate Bar!


Dog ate a dark chocolate bar. What should I do?

You need to think and act very quickly.

For reasons that I explain below, dark chocolate is very dangerous to dogs.

If you can feel a bit of a panic coming on, plan A is to:

Take a deep breath

Estimate how much of the chocolate bar your dog has eaten

Find out from the wrapping what how much cocoa is in the bar

Think how much your dog weighs

Phone your vet.

Or plan B:

Take a deep breath

Estimate how much of the chocolate bar your dog has eaten

Find out from the wrapping what how much cocoa is in the bar

Think how much your dog weighs

Phone the pet poison helpline (which will cost you about $70)

A third option, if you are fairly level headed, is to assess the risk to your dog by using the online calculator which I describe in a lot more detail below.

You do have some time to work things out.

What you can’t do is stick your head in the sand and do nothing. 

What are some of the biggest selling dark chocolate bars?

Why is chocolate poisonous?

Chocolate is poisonous to dogs because it contains a chemical called theobromine- which is a stimulant similar to caffeine.

Whereas the worst this stimulant does for humans is to provide a bit of a “buzz”, it is far more dangerous for dogs.

Dogs experience a buzz too but because their systems cannot cope with the stimulation, in the worst cases this buzz can lead to tremors, seizures and cardiac arrests. 

How much theobromine is poisonous to dogs?

About half of all dogs die when they have a level of theobromine between 100- 200 mg per kg of body weight.

But dogs can start displaying symptoms of chocolate poisoning at as little as 20 mg theobromine per kilogram of weight. 

And levels of theobromine are not the same across all forms of chocolate, because theobromine is found in the cocoa beans.

As we move across the chocolate colour spectrum, the darker the chocolate the higher the concentration of theobromine there is.

Milk and white chocolates are far less “threatening” to a dog’s health.

What do I mean by dark chocolate?

Good question. 

It would be very useful if all “dark” chocolate had the same amount of theobromine in it, but it doesn’t. 

As far as I can see there are four main types of dark chocolate- semi sweet, bittersweet, solid or bakers. 

And they are all defined by the amount of cocoa powder that they have in them.

And the amount of cocoa powder dictates the amount of theobromine. 

Below, I have created a chart with these dark chocolates that compares all of these values and more. 

The serving size for all of these forms of chocolate is 100 g. 

Type% cocoaTheobromineCaffeine
Bakers99%1297 mg80 mg 
Solid70- 85802 mg80 mg
Bitter sweet60- 69632 mg86 mg
Semi sweet45- 59493 mg43 mg
Milk 10- 20205 mg20 mg
White 000

Simply put, the greater the cocoa content the higher the theobromine and caffeine content. 

But although all of that information is useful and helps you understand a bit more about theobromine, it doesn’t give you specific information on your dog’s chances of being poisoned.

And for that you need an online calculator. 

Online calculators

If you are scratching your head thinking that you will never be able to work that out, as long as you have your phone or a laptop closeby, you are best to use an online calculator.

There are quite a few to choose from but this calculator seems easy to use, reliable and it has lots of options of different chocolates which is very handy.

I have outlined the different types of dark chocolate that there are.

Don’t get me started on what defines a dark chocolate bar- things can get even more vague. 

It might have biscuit, caramel or nuts in the center…

How to use an online calculator

The calculator will need three key bits of information from you; the weight of your dog, how much chocolate they ate and the type of dark chocolate that your dog ate. 

It should be clearly labelled on the wrapping as manufacturers like to brag about this kind of stuff. .

Using this calculator I want to show how the size of the dog affects the chances of it becoming poisoned.  

My three test dogs are: 

Henry 7 kg Mini Poodle (my mother in law’s dog)

Sylvie 30 kg Golden Retriever (who is my dog) 

Buster 60 KG Great Dane (a figment of my imagination)

And each dog will eat 50 g of dark “72%” cocoa chocolate. 

Here are the results:

Weight 7 kg30 kg 60 kg
Theobromine 64.75 mg/kg15.11 mg/kg7.55 mg/kg
Caffeine7.76 mg/kg1.81 mg/kg.91 mg/kg
Total72.51 mg/kg16.92 mg/kg8.46 mg/kg
OutcomeSickness & diarrheaSickness & diarrheaShould be OK

What is clear here is how the weight and size of each dog affects the level of theobromine (and caffeine) and how this changes the outcome.

Although Henry and Sylvie can both expect to be vomiting and suffering from diarrhea, we could expect Henry’s vomiting and diarrhea to be more severe because the concentration of theobromine is four times higher than Sylvie’s. 

And for a dog of Buster’s size- he will just be lining up at the counter waiting for seconds!

How long does it take for a dog to show signs of chocolate poisoning?

Those in the know believe that a dog will typically show symptoms of chocolate poisoning within about 6- 12 hours of eating chocolate.

But it could happen a lot sooner for smaller dogs, senior dogs or dogs with an underlying health condition such as a weak heart.

Another key factor in the time that it would take is the quantity of theobromine that your dog has eaten.

Remember, this is not the same as the amount of chocolate that they have eaten.

Your main concern is about dark chocolate, right?

A dog that has eaten a piece of dark chocolate would start to experience symptoms sooner than they would if the chocolate had less theobromine in it. 

What are the symptoms of theobromine poisoning?

There are quite a few symptoms to look out for.

Your dog might show just one symptom or a few.

And for some dogs, with a severe case of chocolate poisoning, the symptoms might change over time and become increasingly severe.

The main ones to look out for are:



Excessive thirst

Sore stomach



Can I cure dark chocolate poisoning with a home remedy?

You absolutely cannot cure chocolate poisoning with a home remedy.

But there are three things that you can do at home to help.

Firstly it is important to act quickly. 

Secondly you need to wash out your dog’s water bowl and fill it with fresh water.

Thirdly, phone the vet and provide as much detail as you can. 

Between your quick thinking and your vet’s expertise your dog will soon be on the road to recovery. 

How can I stop my dog from eating dark chocolate bars?

Hopefully, your dog ate part of a chocolate bar because they were scavenging and found it on the sofa or on the kitchen counter.

That is a much better option than your dog eating it because you were sharing it with him!

Chocolate is one of the few human foods that, no matter how tempting it is, should never be shared with our dogs.

And it is a really difficult one to manage because we all lead busy lives and forget to put things away or tidy up after ourselves now and again.

And another thing that makes it hard is that young children love chocolate and dogs adore young children especially young children eating chocolate!

I’m as guilty as the next person.

Sylvie my Golden Retriever loves my grandson to bits and follows him around everywhere when he comes to visit.

When he has a biscuit or a piece of chocolate her nose could not be any closer to his hand. 

But we do need to exercise extreme care with foods like chocolate. 

James Grayston

My name is James and I love dogs. have owned four Golden Retrievers in the past 15 years. Currently I own two "Goldies"- a five year old and a seven month old. The photo shows me with our youngest when she was about 7 weeks old!