Why Chocolate Is Toxic to Dogs: Our Veterinarian Explains

There's something irresistible about chocolate. Whether you prefer the smooth texture of milk chocolate or the slightly bitter taste of dark chocolate, chocolate has universal appeal. It's no surprise that our canine companions will sneak in a bite of chocolate whenever they get the chance.

Chocolate poisoning in dogs is common because chocolate and chocolate-containing foods are often kept in homes. According to the American Society for the Prevention of Cruelty to Animals (ASPCA), chocolate ranks fourth among the top 10 most commonly reported pet poisons. **Chocolate is toxic to dogs because it contains a compound called theobromine, which can be fatal when ingested by dogs. **Let’s take a closer look at why humans’ favorite snack is a definite no-no for our canine friends.

What Makes Chocolate Toxic to Dogs?

Chocolate is toxic to dogs primarily because of its theobromine content and, to a lesser extent, its caffeine content. These naturally occurring compounds are found in cocoa beans and belong to a group of chemicals called xanthines.

Why can we safely eat chocolate, but our canine companions can't? Unlike humans, dogs aren't good at processing theobromine or caffeine, making them more sensitive to the effects of these chemicals.

Theobromine and caffeine are absorbed through the intestines and spread throughout the body, affecting the heart, respiratory, and nervous systems.

It is important to be aware that chocolate and other chocolate-containing foods may also contain other substances that are toxic to dogs, such as raisins, xylitol, and nuts.

As the old adage goes, the dose makes the poison - and this is especially true for chocolate. Chocolate poisoning depends on the type of chocolate, how much is eaten, and the size of the dog. Small dogs are more at risk of chocolate poisoning.

According to the Veterinary Information Network (VIN), the average toxic dose of theobromine for dogs is 45.3 mg per pound of body weight, while the toxic dose of caffeine is approximately 63.5 mg per pound. However, dogs vary in their sensitivity to these compounds. Typically, dogs may experience mild symptoms such as vomiting and diarrhea when they eat 9 mg per pound of chocolate, heart effects may occur at 18-23 mg per pound, and seizures may occur at doses of 27 mg per pound or more.

The exact amount of xanthines in chocolate varies due to variations in cocoa beans and chocolate recipes. Generally speaking, the darker and more bitter the chocolate is, the more dangerous it is to dogs. Dry cocoa powder contains the highest concentration of xanthines (about 800 mg per ounce), followed by baking chocolate (about 450 mg per ounce), semisweet chocolate and sweet dark chocolate (about 150-160 mg per ounce), and milk chocolate (about 64 mg per ounce). White chocolate has negligible concentrations of this toxic compound.

The Merck Veterinary Manual has a chocolate poisoning calculator that can be used to calculate the total amount of xanthines a dog has ingested and indicate whether your dog needs veterinary treatment based on the dog's size and the type and amount of chocolate consumed. You can find the calculator here.

For example, a medium-sized dog weighing 40 pounds would only need to eat about 1 ounce of baking chocolate, or 9 ounces of milk chocolate, to show symptoms of poisoning, while a small dog weighing 10 pounds would probably show symptoms of poisoning after eating about 1/4 ounce of baking chocolate, or 2 ounces of milk chocolate.

What are the symptoms of chocolate poisoning?

Clinical symptoms depend on the dose of xanthines ingested. For many dogs, the most common early signs of chocolate poisoning are diarrhea, vomiting, restlessness, a rapid heartbeat, and panting. These initial symptoms may lead to muscle tremors, seizures, and irregular heartbeats. If large amounts of chocolate are ingested, it can be fatal. Even if the amount of chocolate ingested is not toxic, dogs can still become ill and may develop pancreatitis due to the high fat content of chocolate.

Symptoms of chocolate poisoning appear about 1-4 hours after ingestion, but sometimes become visible after 6-12 hours. If a large amount of chocolate is consumed, symptoms may last for several days because theobromine stays in the blood for a long time. Theobromine may also be reabsorbed from the bladder.

What should I do if my dog eats chocolate?

Stay calm and try to figure out how much chocolate your dog ate and what type of chocolate it ate. Call your local veterinarian or pet poison hotline, or use the chocolate poisoning calculator in the aforementioned Merck Veterinary Manual to see if your dog has ingested a toxic amount of chocolate. If your dog has ingested a toxic amount of chocolate, you should see your veterinarian as soon as possible. If you are not sure how much chocolate your dog has eaten, you should also take your dog to the veterinarian as soon as possible. The sooner your dog receives treatment, the better the prognosis.

How is chocolate poisoning diagnosed?

Unfortunately, the symptoms of chocolate poisoning are not specific and can mimic a number of other illnesses, such as other drug poisonings, neurological disorders, or metabolic disorders. Diagnosis is based on a known history of chocolate ingestion or the ingestion of foods containing chocolate. In the veterinary office, chocolate may also appear in the vomitus of a dog after it has been induced to vomit.

What is the treatment for chocolate poisoning?

There is currently no specific antidote for theobromine and caffeine. If caught early, your veterinarian will induce vomiting to empty the stomach of any chocolate that may have been ingested and prevent further absorption of the toxic compounds (do not try to induce vomiting yourself). The dog will be treated with multiple doses of activated charcoal to prevent theobromine and caffeine from being absorbed into the body. If treatment is started early and the dog has not yet shown symptoms of chocolate poisoning, this may be the only treatment needed.

Dogs that have shown symptoms of chocolate poisoning will require supportive care, such as intravenous fluids and control of seizures. They may also require blood tests to monitor organ function and electrolyte levels.

All dogs that ingest chocolate should be monitored for signs of vomiting, diarrhea, restlessness, hyperactivity, and seizures. Their blood pressure and heart should also be closely monitored.

What is the prognosis after chocolate poisoning?

Chocolate poisoning usually resolves within 48 hours, and animals that receive veterinary treatment generally have a good prognosis.

How can I prevent this from happening to my dog?

Keep all chocolate and foods containing chocolate out of reach of your dog. Do not share any chocolate or foods containing chocolate with your pet. Educate all family members, including children, about the dangers of chocolate poisoning. Be especially vigilant during celebratory times, such as birthdays, the holiday season, and Easter, when chocolate may be more likely to be present in the home.