Chocolate Toxicity in Dogs

How many times have you been eating that chocolate chip cookie when you look over and see those sad puppy dog eyes staring at you?  You remember hearing that chocolate is toxic to dogs.  But what makes chocolate toxic to dogs and why is it that some dogs ingest it and don’t get sick?  Here are some facts to clear up some of the confusion surrounding chocolate toxicity in dogs. 

                Chocolate can indeed be toxic to dogs.  In fact, it is one of the 20 most reported poisonings.  The ingredient in chocolate that causes the toxicity is theobromine.  The minimum toxic level of theobromine is 100-200mg/kg with 250-500mg/kg being the level at which half of the dogs would die as a result of consuming chocolate.  So what does that mean as far as how much chocolate is toxic?  The level of theobromine varies depending on the type of chocolate.  The levels of theobromine are listed below:

Given these levels, 4 oz of milk chocolate contains about 240mg of theobromine. Considering that the average chocolate bar contains 2-3 oz of milk chocolate, it would take 2-3 candy bars to produce toxicity in a 10 lb dog.    However, a single ounce of baking chocolate could produce severe toxicity in the same size dog.

                So, how does chocolate make dogs sick?  Theobromine causes the release of certain substances, norepinephrine and epinephrine, that cause an increase in the dog’s heart rate and can cause arrhythmias.  Other signs seen with chocolate toxicity can include increased urination, vomiting, diarrhea or hyperactivity within the first few hours.  This can lead to hyperthermia, muscle tremors, seizures, coma and even death.

                What should be done if a dog does ingest a toxic amount of chocolate?  If it has been less than 2 hours, the dog should be made to vomit.  Unfortunately, chocolate tends to form a ball in the stomach and may be difficult to remove.  Supportive care should be provided for any other signs the dog is exhibiting.

                 Though it may not be harmful to the dog in small quantities, it is safer to avoid giving chocolate to dogs in general.  As with everything else, it’s better to be safe than sorry.     

Created by Dawn Haas DVM Class of 2003