Why Is Chocolate Bad for Dogs?

How much chocolate can kill a dog and what to do if your dog eats chocolate

Little mongrel dog with chocolate
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Chocolate is bad for dogs because it contains theobromine, an alkaloid compound found in the cacao plant, from which chocolate is derived. Chocolate also contains caffeine, which, like theobromine, is classified as a methylxanthine, a compound found in large quantities in tea, coffee, and chocolate, that humans have consumed for centuries because of its psychoactive properties. While people can easily digest these compounds, dogs cannot, and even small amounts of chocolate can lead to a range of symptoms including nausea and vomiting, with death occurring in very serious cases. In general, darker and bitter chocolates are more dangerous for dogs.

Chocolate poisoning can present a wide range of symptoms, making it sometimes difficult to initially diagnose.

Warning

Reach out to your veterinarian or the ASPCA poison control center immediately if you suspect your dog has consumed chocolate.

What Makes Chocolate Harmful to Dogs?

Most pet owners know that dogs and chocolate don't mix, but many people aren't sure precisely why. Chocolate is derived from the roasted seeds of the cacao plant, which contains two primary components that are toxic to dogs: theobromine and caffeine. Part of the methylxanthine group of compounds abundant in human food and beverages, people can easily digest these compounds, with the half-life (the time it takes for the concentration of a substance in the body to decrease by half) of theobromine being only between two and three hours on average.

In dogs, the half-life of theobromine is 18 hours on average. This long processing time is part of what makes chocolate so dangerous for dogs, as high concentrations of these compounds remain in the animal's system. Theobromine and caffeine stimulate the heart rate and nervous system of dogs, which is why hyperactivity is often one of the first symptoms of chocolate poisoning. While chocolate poisoning is rarely fatal, it is important to seek immediate medical attention for your pet (chocolate is also toxic to cats).

What Is Theobromine?

Theobromine is a bitter alkaloid compound that is in the same family of compounds as caffeine — methylxanthines, which contribute to the state of alertness people feel when they drink tea and coffee. In dogs, these compounds metabolize slowly.

Theobromine primarily affects a dog's central nervous system, cardiovascular system, and respiratory system, and it also has a diuretic effect.

How Much Chocolate Can a Dog Eat?

How much chocolate can kill a dog will vary depending on the size and breed of dog. A toxic amount of chocolate for a Chihuahua could produce little to no symptoms in a Great Dane. In general, bitter, darker, chocolates are more dangerous to dogs, because these chocolates contain more cacao, meaning that they also contain more theobromine and caffeine. According to the FDA, theobromine content in chocolate can vary as follows:

  • Milk chocolate contains 44 mg of theobromine per ounce (704 mg/lb)
  • Semisweet chocolate chips contain 150 mg per ounce (2,400 mg/lb)
  • Baking chocolate contains 390 mg of theobromine per ounce (6,240 mg/lb)

Dark chocolates contain a range of theobromine, with amounts as high as 450 mg of theobromine per ounce. White chocolate poses a very low risk of chocolate poisoning, with only 0.25 mg of theobromine per ounce.

In general, the minimum toxic theobromine dose in dogs ranges from 46 to 68 mg of theobromine per pound of dog weight. Half the dogs that consume 114 to 228 mg of theobromine per pound of dog weight or greater can die. There are other factors at play, including how sensitive a particular dog is to these compounds.

My Dog Ate Chocolate, What Do I Do?

If you suspect your dog has eaten chocolate, begin monitoring it carefully and reach out to your veterinarian or the ASPCA poison control center. If it exhibits any symptoms, seek veterinary attention immediately. If you know your dog has eaten chocolate, the safest thing to do is take it to the vet.

Symptoms of Chocolate Poisoning in Dogs

  • Vomiting
  • Diarrhea
  • Rapid heart rate
  • Restlessness
  • Hyperactivity
  • Urinating more
  • Muscle spasms
  • Seizures
  • Other neurological signs

Symptoms of chocolate poisoning in dogs can begin around two hours after initial consumption, though it can take as long as 24 for them to appear, and they can last as long as three days. The first signs of poisoning include vomiting, haematemesis (vomiting blood), and polydipsia (abnormal thirst). Medically, other signs may include hyperexcitability, hyperirritability, tachycardia, excessive panting, and muscle twitching. Effects may progress to cardiac arrhythmias, seizures, and even death in severe cases.

Any long-term effects of chocolate poisoning will depend on the severity of poisoning, with dogs recovering completely in the majority of cases. Repeated poisonings may over-stimulate the dog's central nervous system, which is potentially harmful, and the fat content of chocolate could also lead to obesity or pancreatitis if a dog eats it often.

Treatment

Only a veterinarian can provide proper treatment for your pet and should be the first person you consult in the event of a suspected poisoning. The sooner theobromine is removed from an animal's system, the healthier it will be. At a clinic, the first step may be gastric decontamination — a drug is administered to empty the dog's stomach contents and stop the absorption of theobromine and caffeine.

Next, vets may administer activated charcoal, a powdered material that can bind compounds, as well as oxygen and fluids, when needed. There are also specific medications a dog may be given depending on the severity and symptoms of poisoning, such as Diazepam for seizures or hyperexcitability, beta blockers for high heart rate, or Atropine for low heart rate. Dogs typically recover within three days.

At home, if your dog has consumed chocolate, it is important to take it for walks often to encourage urination, because theobromine can be reabsorbed from the bladder due to its long half-life. Ample fluids will also help remove harmful methylxanthines. Like most people, dogs will eat chocolate if they find it, so in general it is also important to keep chocolate far from where dogs can reach, in well-sealed containers, to prevent poisoning in the first place.

View Article Sources
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  2. Leave Chocolate Out of Rover's Celebrations.” U.S. Food & Drug Administration.

  3. Finlay, Fiona, and Simon Guiton. “Chocolate Poisoning.” BMJ, vol. 331, no. 7517, 17 Sep. 2005.