Charley, a 3 year old female Cavalier King Charles Spaniel who needed emergency treatment after eating a whole box of chocolates

“Death by chocolate” may be a popular name for sumptuous desserts in restaurants, but to my knowledge, a human has never died after eating too much of the stuff. Unfortunately, hundreds of pet dogs around the world do die from chocolate poisoning, and last week , Charley was nearly a victim.

There are two reasons why chocolate is so dangerous to dogs. Firstly, it contains a chemical called “theobromine”, which is a stimulant similar to caffeine. The metabolism of a dog is unable to deal with theobromine as rapidly as in humans, and so after eating chocolate, it rapidly accumulates to toxic levels in the bloodstream. The toxic dose of chocolate varies according to the type, since each contains a different level of theobromine. Vets have reference tables that list the life-threatening amounts of dark, milk, or white chocolate. In general, the darker the chocolate, the greater the risk to the dog.

The second reason that dogs die from chocolate poisoning is that they do not know when to stop. If a human decides to have a complete chocolate binge, they might manage 2 or 3 large bars of chocolate. A dog that likes eating chocolate often does not seem to have a “stop” mechanism, and they will often consume all of the chocolate in front of them, which could be the equivalent of as much as a dozen bars.

Charley is a small dog, weighing not much more than a cat, but she has a massive appetite for chocolate. Nobody can remember when she had her first taste of chocolate, but she has certainly learned to love it. Her first chocolate crisis happened last year, when she somehow noticed that an unopened Easter egg has been placed on a shelf out of her reach. She climbed up onto a chair, then managed to clamber onto the shelf to grab the egg. She managed to eat the entire egg before anyone noticed. On that occasion, her misadventure was only discovered at a late stage, and it was too late to visit the vet. She had an upset stomach, but did not suffer any other undue consequences. She was fortunate that she had only eaten a small milk chocolate egg.

Last week, Charley had a much bigger chocolate crisis. Kelly’s fiancée Declan had returned from a trip overseas, and he had brought her a large box of luxury Belgian chocolate. Kelly ate a few of her favourites, then closed the box, and left it on her bedside table. The bedroom door is closed during the daytime, and her two Cavaliers, Charley and Susie, were confined to the kitchen area when she was out at work. When Kelly came back in the evening, she greeted the dogs, and gave them their supper. She then changed out of her work clothes before going into the garden. She did not notice that she had left the bedroom door open.

A few minutes later, when she came back into the house, she heard a loud rustling noise coming from the bedroom. She rushed in, but it was too late. The empty chocolate box was on the ground, and both dogs were rummaging through the plastic packaging. Charley had chocolate stains around her mouth, and Susie looked equally guilty.

Kelly knew about chocolate poisoning, and so she rushed both dogs down to our vet clinic. We immediately gave them both an injection that caused them to vomit repeatedly. Poor Susie brought up her dinner,  with not even a trace of chocolate. Charley, on the other hand, vomited time after time, and kept on bringing up bowlful after bowlful of pure chocolate. The sequence of events was now very clear. Susie was an innocent bystander, and Charley was both the instigator and the sole guilty party. We rapidly worked out that she had eaten around 600g of chocolate, which on a weight-for-weight basis, is like a human being eating ten entire boxes of  rich chocolates. Kelly does enjoy chocolates herself, but she reckons that could only eat three or four chocolates before feeling full.  Charley had managed to eat over twenty, which is the equivalent of a human having hundreds of individual chocolates.

I knew from my reference sources that only 100g of dark chocolate could have fatal consequences for Charley, and so emergency action was needed.  Her stomach had been effectively emptied by the vomiting, but we also gave her repeated doses of activated charcoal, which helped to absorb toxic chemicals in the bowel before they had been absorbed into the bloodstream. She was set up on an intravenous drip, to flush out her kidneys, removing any remaining toxins from body as rapidly as possible. Her heart rate was monitored twice hourly, because a rapid heart rate is the first sign of chocolate poisoining. If a dog has eaten a toxic dose, the most common cause of death is a heart attack due to the rapid, abnormal and irregular heart rhythms that develop.

Charley was carefully monitored overnight, and her heart rate went up and up at first, reaching almost 200 beats per minute.  However, she remained comfortable, and around eight hours after her pig-out, her heart began to slow, and we knew that she was going to be OK.

I saw her for a check up a few days later, and she was completely back to normal.  Sadly, dogs do not learn lessons after experiences like this. From now on, any chocolate in Kelly’s household is going to need to be under lock and key.


  • Chocolate contains a chemical that is toxic to dogs
  • Many dogs indulge in major chocolate binges if they have an opportunity
  • Emergency treatment, given immediately after the binge, can save a dog’s life

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Please note that I am unable to answer veterinary questions in comments. If you have questions or concerns about your pet's health it is always better to contact your vet.

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