Chocolate toxicity in dogs is often misunderstood by dog owners. How much chocolate will cause a seriously harmful reaction for dogs? Should you worry if your dog eats a single chocolate covered almond, or if he wolfs down a brick of Baker’s chocolate?

Chocolate contains the compound theobromine, which is toxic to dogs in large amounts. Tiny amounts of theobromine are unlikely to cause chocolate toxicity in dogs, but large amounts can result in hyperexcitability, muscle tremors, and even cardiac arrest.

Theobromine and Chocolate Toxicity

Theobromine is a xanthine compound belonging to the same family as caffeine and theophylline (a drug used to treat bronchial disorders such as COPD and asthma).

Chocolate toxicity in dogs requires a large amount of theobromine, approximately 100 to 150 mg for every kilogram that the dog weighs.

The severity of chocolate toxicity depends on the size of the dog, the concentration of theobromine in the chocolate and the dog’s personal sensitivity to theobromine’s effects.

Symptoms of Chocolate Toxicity in Dogs

Symptoms of chocolate toxicity in dogs are similar to an overdose of caffeine, or any other xanthine compound. Theobromine affects the dog’s nervous system, his cardiovascular system and his peripheral nerves (nerves in the body and organs).

Symptoms of chocolate toxicity include:

  • diarrhea
  • hyperexcitability
  • hyperirritability
  • increased heart rate
  • increased urination
  • muscle tremors
  • restlessness
  • vomiting.

Anyone who’s accidentally drunk too much coffee will recognize the symptoms of hyperexcitability, irritability, and increased urination and can relate to how theobromine affects dogs.

Cardiac Arrest and Theobromine Chocolate toxicity in dogs can have serious consequences. Theobromine, in large enough amounts, can cause hypothermia, seizures and cardiac arrest. While coma rarely results from theobromine overdose, severe cases of chocolate toxicity in dogs can result in death.

Treating Theobromine Overdose

Chocolate overdose in dogs has no antidote: treatment focuses on controlling symptoms until the theobromine leaves the dog’s system. Because dogs cannot metabolize chocolate as effectively as humans, theobromine can remain toxic for up to seventeen hours.

If your dog shows any symptoms of chocolate toxicity, contact your veterinarian immediately.

Hopefully, you will know how much chocolate your dog has eaten. If not, the veterinarian may induce vomiting within the first two hours of symptoms. The veterinarian may also administer activated charcoal to inhibit absorption of the theobromine.

If chocolate toxicity results in neurological symptoms, such as muscle spasms or seizures, anticonvulsants may be required until theobromine symptoms run their course.

In the most severe cases, dogs suffering from theobromine toxicity can go into cardiac arrest. Oxygen therapy, fluids and intravenous medications may be required to protect the dog’s heart.

Milk Chocolate Toxicity in Dogs

Milk chocolate contains less theobromine than other types of chocolate, so milk chocolate toxicity in dogs tends to be less severe than Baker’s chocolate.

Unless large amounts of milk chocolate are consumed, theobromine symptoms caused by milk chocolate are often limited to diarrhea. Diarrhea may develop up to 24 hours after eating the chocolate.

To treat chocolate toxicity caused by milk chocolate, provide the dog with plenty of fluids to keep him hydrated. Further veterinary treatment may be required if severe dehydration results from diarrhea.

Levels of Theobromine in Chocolate

Not all chocolate contains the same amount of theobromine, so quality, as well as quantity must be considered when dealing with chocolate toxicity in dogs. Here are the average amounts of theobromine found in different types of chocolate:

  • milk chocolate : 44 mg of theobromine per ounce.
  • semisweet chocolate : 150 mg of theobromine per ounce.
  • Baker’s chocolate : 390 mg of theobromine per ounce.

In practical terms, candies coated with chocolate have less theobromine than solid chocolate candy. Chocolate cookies and chocolate ice cream contain only small amounts of chocolate, and are less likely to cause chocolate toxicity in dogs.

Because baking chocolate and good quality chocolates contain large concentrations of theobromine, they are much more likely to cause chocolate toxicity in dogs than other types of chocolate.

How Much Chocolate is Too Much?

Knowing that 100 mg/kg of theobromine causes chocolate toxicity in dogs, the following amounts of chocolate are toxic:

  • milk chocolate : one ounce chocolate per pound of dog.
  • semisweet chocolate : one ounce chocolate per three pounds of dog.
  • Baker’s chocolate : one ounce of chocolate per nine pounds of dog.

Chocolate Toxicity in Dogs May Be Cumulative

Although incidents of chocolate toxicity in dogs have long been considered one-time poisonings recent evidence suggests that some dogs may over time build up sensitivity to theobromine. In other words, small amounts of chocolate may not prove toxic, but continued consumption can eventually lead to chocolate toxicity in dogs.