Chocolate Toxicity | Why is chocolate toxic to dogs?

by Nancy Boland

Dogs are known for eating things when they are not supposed to, especially when they are young as puppies love to explore. Couple this with a dogs excellent sense of smell, and you may run into trouble if you don’t keep chocolate hidden. Chocolate is toxic to dogs.

Chocolate is derived from the roasted seeds of Theobroma cacao, which contains two toxic ingredients to your dog: caffeine and theobromine. We can easily metabolise theobromine, but dogs process it much slowly, allowing it to build up to toxic levels in their system. If ingested, these two ingredients can also lead to various medical complications and may even prove fatal if ingested in large quantities.


  • Vomiting
  • Diarrhea
  • Increased body temperature
  • Muscle rigidity
  • Rapid breathing
  • Increased heart rate
  • Low blood pressure
  • Seizures
  • Advanced signs (cardiac failure, weakness, and coma)

The amount and type of chocolate, as well as the size of your dog all make a difference in determining the severity of the poisoning. A large dog can consume more chocolate than a smaller dog before suffering ill effects.

A single piece doesn’t contain a large enough amount of  theobromine to harm your dog; however, if you have a small dog that has eaten a box of chocolates, you need to call your vet immediately.

The highest theobromine concentrations are found in baking and dark chocolate, whilst milk and white chocolate contain lesser but still concerning levels. Chocolate flavoured products have the lowest theobromine concentrations. Fat, sugar, and other ingredients (alcohol, preservatives, sugar alcohols, etc.) can also exacerbate the signs of chocolate toxicity.

chocolate 1


Your vet will perform a complete physical exam, including a chemical blood profile, electrolyte panel and a urinalysis. These tests will help determine if there is a chocolate/caffeine overdose.
Blood can also be taken to test for theobromine concentrations, while an ECG is performed to help determine if the heart is showing any abnormalities in rhythm or conduction of heart beats.


Your dog should be seen immediately by your veterinarian. It is common practice to induce vomiting and control any seizures, should they occur with chocolate poisoning. In the meantime, keeping your dog in a cool, calm, and quiet space is always beneficial.

Fluids will be given to keep your dog to keep it hydrated as its condition improves. To avoid any further problems, a bland diet of plain, boiled chicken with white rice is recommended.

Click here to read more about “What should I do if my dog has eaten chocolate“.


As always prevention is better than cure, so always remember to keep human treats well out of the dog’s height as there is no antidote to chocolate toxicity.

Click here to see the Top 10 Dog Poisons That You May Not Know About.

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