Gazette Vet: When Dogs Eat Chocolate

Dogs and chocolate.

Happy Holidays everyone! During this most wonderful time of year, there is definitely a lot of chocolate floating around people’s houses. I know this because we start fielding several calls every day about someone’s dog eating chocolate.

Fortunately, most people are aware that chocolate is toxic to dogs. But how much? And does the type of chocolate matter? Here’s help figuring out what a “no problem” dose of chocolate is for your dog versus what a “very toxic” dose of chocolate is.

First, let’s review why chocolate is toxic to dogs. Chocolate contains a compound called theobromine. Too much theobromine in any mammal species can cause gastro-intestinal upset (vomiting and diarrhea), neurologic problems like tremors, convulsions, and seizures, and heart problems such as a rapid heart rate, low blood pressure, and arrhythmias. We humans can metabolize (our bodies can break it down) theobromine quickly, so fortunately we can consume a lot of chocolate without any risk of toxicity. Yay!

Dogs, however, do not metabolize theobromine well, so it just hangs around in the bloodstream. This is why they are quite susceptible to chocolate toxicity. Cats are also susceptible, by the way, but they are generally too smart and don’t have enough of a sweet tooth to consume chocolate in the first place.

Now let’s go back to how much and what kind. Chocolate comes from the cacao tree seeds. Cacao seeds are harvested, dried, roasted, ground and pressed to produce cacao liquor–100 percent cacao chocolate! Typically, this is mixed with other ingredients to give us the different chocolate products that we love. Here is a rough breakdown of how much theobromine is in each of the main chocolate types:

  • Dry cocoa powder – 800mg theobromine/ounce
  • Unsweetened/Baker’s chocolate – 450 mg/oz.
  • Semisweet chocolate – 150-160 mg/oz.
  • Milk chocolate – 50mg/oz.

As you can see, cocoa powder and baker’s chocolate are by far the most toxic forms of chocolate. Milk chocolate is fortunately not as toxic.

Still, how do these numbers actually relate to you when your dog just ate half a tray of Christmas cookies?

Here’s a secret: we cheat! We use a chocolate toxicity calculator to determine what type of treatment your dog needs. Fortunately, these calculators are readily available online, giving you an opportunity to make some quick calculations before calling your vet.

For these examples, I am using the chocolate calculator I found online by searching “chocolate calculator” into google (

Let’s start with some examples. For each of these we’re going to have a 50-pound dog and a 15-pound dog.

Let’s start easy and say that your dog got into some chocolate chip cookies. You estimate that there were three traditional-recipe cookies there. Because you are smart, you do some cooking math. You used semi-sweet chocolate chips and used the recipe on the back of the bag. The batch made 12 cookies, and it was a 10-oz. bag of semisweet chocolate chips. So, 10 ounces divided by 12 cookies equals 0.83 oz. of semisweet chocolate per cookie. Three cookies equal 2.5 oz.

Now let’s go to the chocolate calculator. It first asks you to plug in your dog’s weight. Easy! Let’s start with the 50-pound dog. Next, it asks you the chocolate type—you choose semisweet chocolate. Last, its asks you approximately how many ounces. You enter 2.5 and voila! It calculates how concerned we need to be and fortunately the answer is that this will only cause mild toxicity—possibly some vomiting and diarrhea and maybe some restlessness (don’t forget, chocolate also has caffeine!). You find yourself relieved that you don’t need to go to the Emergency Room, but hope not to have any accidents.

Let’s repeat this amount for the 15-pound dog. Same thing: three cookies, same recipe. This time, the calculator screams at you to seek immediate medical attention because your dog is going to have a severe problem due to all that chocolate! Off to the ER!

Now let’s repeat this scenario, but assume we used milk chocolate chips. Phew! Milk chocolate has so much less theobromine that even for the 15-pound dog, we should only expect mild toxicity.

Let’s do one more chocolate example, baker’s chocolate. You were making some chocolate brownies from scratch and are using those baker’s chocolate squares. Each square is one ounce of unsweetened baker’s chocolate. You accidentally knocked two squares of the counter and before you could yell at your dog, she immediately gobbled them up!

When we plug the 50-pound dog into the chocolate calculator, we now find that there is moderate toxicity expected, definitely some vomiting and diarrhea, and maybe some elevated heart rate, and restlessness. This makes you nervous and you call your vet, who is still open, thankfully. Not a lot of chocolate for a 50-pound dog, but enough to cause some problems. Of course, in this example, the 15-pound dog is not so lucky.

So, what do we, the veterinarians, do when we see dogs with chocolate toxicity? After calculating that yes, enough chocolate has been ingested to be concerning, the first thing we will do is make them vomit. We give an IV injection of apomorphine, a drug that will quite impressively and immediately cause about three minutes of intense vomiting. Depending on how much chocolate the dog ate, we will either treat conservatively with some subcutaneous fluids or perhaps treat more aggressively with IV fluids and other measures to help with the toxicity.

I have seen dogs come in late in chocolate toxicity. They don’t look good. They look like they got into poison: drooling and vomiting, irregular heart rate and breathing, and tremoring/seizuring. These cases are scary because you never quite know how their body is going to react. Fortunately, we can save most, but there are some who just aren’t so lucky. Most of these unlucky ones were simply brought in too late.

Enjoy this wonderful time of year, and enjoy tons of chocolate! Just keep it away from the dogs!


Please enter your comment!
Please enter your name here