Can Dogs Eating Chocolate Cause Long-Term Health Problems?

A reader wonders whether consumption years ago is contributing to erratic behavior in her dog.


Chocolate toxicity season begins a week before Halloween and ends on Valentine’s Day. During the heaviest part of the season (around Christmas), I treat two or three dogs every night at the emergency clinic for complications associated with chocolate.

My Jack Russell Terrier is about 11 and comes from excellent breeding stock. Due to inattentive children, she had multiple incidents of chocolate consumption when she was younger. She displayed all of the major symptoms but recovered.

She has continued to have many of the same neurological symptoms several times a year, recently more frequently. These include nervousness, pacing, restlessness, panting, and hovering near one of “her humans.” She tries to sleep on our heads, won’t leave our sides, frequently tripping us because she gets tangled in our feet. We moved to Alaska this year and don’t have a family vet. Could this be a long-term result of the earlier poisoning?


Chocolate ingestion can cause trouble for dogs in two ways. First, chocolate contains two toxins: caffeine and theobromine. Also, the cocoa butter, creamy nougat, and other rich additives present in many types of chocolate can cause intestinal distress or, in severe cases, pancreatitis.
Caffeine and theobromine are related. As anyone who has ever consumed coffee knows, caffeine causes increased mental activity and stimulation of the gastrointestinal tract. Dogs experience these symptoms as well. However, dogs are very sensitive to caffeine and theobromine. Dogs who consume significant quantities of the toxins may suffer profound agitation and disorientation, heart arrhythmias, seizures, and death.
Even dogs who don’t suffer severe symptoms of chocolate toxicity may be at risk of pancreatitis when they consume the tasty treat. The pancreas, which produces digestive enzymes, becomes overwhelmed by the rich products mixed into many chocolates. Potential symptoms include vomiting, diarrhea, poor appetite, and abdominal pain. Diabetes is a potential long-term consequence of pancreatitis.
In her book, The Willpower Instinct, Kelly Mcgonigal wrote of researchers who were attempting to study the differences in brains of people who like chocolate and those who don’t. The researchers struggled because it’s almost impossible to find a person who doesn’t like chocolate (Mcgonigal wrote that it took a year to find 11 people). It seems that dogs share this trait with people — dogs generally love chocolate. And they can smell it from hundreds of feet away. As a result, dogs eat chocolate all the time.
Which brings us to the good news. Although chocolate consumption is common, and the effects are potentially fatal, I have yet to see a case of long-term deleterious neurological effects from chocolate toxicity in any dog. Both of the toxins are excreted relatively rapidly, and neither should cause permanent damage (although it’s theoretically possible through secondary effects, such as brain damage sustained during a prolonged seizure — something I have yet to see happen).
Susan, the behaviors you describe certainly do resemble very mild chocolate toxicity. However, you also mention that your dog is a Jack Russell. This breed is well known for “nervousness, pacing, restlessness, panting, and hovering near one of ‘her humans.'” Your dog may be displaying breed-related behavior changes as she ages. The stress of your recent move may also be contributing. It is not likely that her earlier dalliances with chocolate are playing a role.
Although I have never met a dog with long-term effects from caffeine or theobromine, I unfortunately cannot say the same for pancreatitis. Dogs that develop pancreatitis after consuming chocolate may be predisposed to recurrent episodes of vomiting or diarrhea. And, as I mentioned before, they are at increased risk of diabetes.
Therefore, I do not hesitate to recommend that you, rather than your dog, do the chocolate eating in your family.

Got a question for Dr. Barchas? Ask our vet in the comments below and you might be featured in an upcoming column. (Note that if you have an emergency situation, please see your own vet immediately!)

3 thoughts on “Can Dogs Eating Chocolate Cause Long-Term Health Problems?”

  1. My Dogg ate a comically large bar of dark chocolate right after Christmas and I took her to the hospital where she was watched overnight. Now about two months later, she stopped eating, we refusing food and anything she ate she threw up a few hours later, accompanied with watery diarrhea.
    She drinks more water than usual and she's now interested in eating food but I wake up each morning to a pile of vomit and diarrhea she's left for me. I'm attributing this to some kind of organ failure since the chocolate incident? Is this possibly related?

  2. Thank you for the most intelligent response to the perennial question about dogs consuming chocolate. My 6 year old standard poodle practically demands that I give him some chocolate. He knows when I have accessed it from my hiding place when he's 3 rooms away. I can't stand it! We discourage "begging" and don't pay it off after we're done. He has a very nutritious and tasty meal daily and has his favorite kibble which is salmon and sweet potatoes with other nutrients standing by whenever he wants a snack. I love it that most poodles are self regulating with the amount they eat and rarely overeat. My only problem lately is finding a sidekick for him to play with. We've been combing the shelters for quite awhile. We're in our 70's and don't want a puppy – it would be adopted by our children, but we don't want the digging and chewing that goes with a puppy. Thanks again for your intelligent answers.

  3. Pingback: 7 Tips for Creating a Dog-Friendly Easter Egg Hunt – The Dog Delight

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