Monthly Doctor’s Blog: Chocolate Toxicity

Every month, the doctors of AtlasVet are writing a blog post to help pet owners with common questions. 

For October & Halloween:  Chocolate Toxicity by Dr. Matthew Antkowiak!

Just in time for Halloween, we tackle the most discussed and maligned canine toxin:   Chocolate!

Poor Chocolate.  How can one of life’s greatest pleasures get such a bad rap?  

AtlasVet and local veterinary ERs get weekly calls and visits around the ingestion of chocolate, and there is an increased volume around chocolate-centric holidays like Halloween.  In this blog, we are going to examine just how bad it is for your dog to ingest that chocolate bar.

First, we must understand what is “bad” about chocolate.  The primary toxic principles involved with chocolate are in a family called methylxanthines:  theobromine and caffeine.  What are the toxic effects?  Hyperexcitability, nervousness, fast heart rate.   And in more severe cases; muscle tremors, vomiting or seizures.  The same effects we might feel from polishing off an entire pot of coffee…or two…or three.

Sounds horrible, right?

Deep breath.  Before we start throwing away all the chocolate in our homes, let us examine just HOW MUCH chocolate needs to be ingested before our canine friends start having these clinical signs. 

1)      How much theobromine is in chocolate? On average, milk chocolate (Snickers, Hershey bars) contains 50-60 mg of theobromine/oz, semisweet chocolate (chocolate chips) contains 150mg/oz, baker’s chocolate 390mg/oz 

2)      How much theobromine does it take to cause problems? Mild toxic signs appear at roughly 20mg per kilogram of body weight, more severe signs at 40-50mg per kilogram.

3)      Doing some math, we get canine clinical signs of toxicity at 1.5 ounces milk chocolate per 10 pounds of body weight, 0.6-ounce semisweet chocolate per 10 pounds of body weight, and a mere 0.2-ounce of baker’s chocolate per 10 pounds of body weight.

So, your 80lb Rhodesian Ridgeback needs to eat about ¾ lb of milk chocolate to get mild theobromine toxicity and 1.5lbs to have moderate to severe signs.  Your 10lb Yorkie?  1.5oz (roughly a Hershey bar) of milk chocolate for mild signs and 2 Hersey bars (3.0oz) for severe signs.  However, those same dogs would only have to eat 1.5oz and 0.2oz of baker’s chocolate respectively to have the same signs. 

Not sure where your dog falls?  Here is a handy chocolate toxicity calculator

Please note:  The sugar and fat content of the chocolate may very well cause diarrhea and vomiting.  This is not the same as theobromine/caffeine toxicity but may require treatment like any other dietary indiscretion.

Bottom line: 

1)      Size matters – Small amounts of milk chocolate certainly will not kill your dog and may not even harm him/her, however the size of your dog, the concentration of theobromine in the chocolate and the amount ingested play a huge part in how they will be affected.

2)      Call – When in doubt about something your pet has ingested, including chocolate, call a poison control center, your veterinarian or the closest emergency vet.  My favorite is the ASPCA Poison Control Center  It is cheaper than an ER vet visit and they have trained veterinarians on duty 24 hours a day with a comprehensive list of possible pet toxins and how to proceed if ingested.

Further reading:

For more information on Chocolate and it potential effects on your dog, click here

For a list of other “people foods” to avoid with your pet, click here