Who can resist those wide puppy-dog eyes staring up at us while we enjoy a snack? As tempting as it may be, if that snack happens to be a bar of chocolate, do not give in! The myth that chocolate can kill dogs is far from an urban legend. It is tragically based on fact, and has thousands of pet owners year-round calling the emergency vet, especially around holidays like Halloween, Valentine's Day, or Easter, when chocolate is a strong part of the modern holiday culture.
The type of chocolate (white, dark and milk chocolate) plays a part in how dangerous it is to your dog. Cocoa beans contain a chemical called theobromine, a compound closely related to caffeine that affects the nervous and cardiovascular systems, peripheral nerves, and is a known diuretic. Dogs do not have the enzyme to properly break down this chemical, so they feel the effects of it much more strongly than we do. White chocolate contains the lowest amount of theobromine at about 1 mg/oz., while Baker's chocolate at 400-450 mg/oz. is the most toxic. Hot chocolate mixes (12 mg/oz.), milk chocolate (40-60 mg/oz.), and semi-sweet chocolate (150-250 mg/oz.) makes up the middle range of this toxicity. It takes about 100 to 150 milligrams of chocolate for every 2.2 pounds of body weight to cause a toxic reaction in dogs. To give you a general idea, a ten pound dog would be affected by 8 ounces of milk chocolate and 1 ounce of Baker's chocolate. A thirty pound dog would be affected after 1 1/2 pounds of milk chocolate and 3 3/4 ounces of Baker's chocolate and a fifty pound dog would be affected after 3 pounds of milk chocolate and 5 1/2 ounces of Baker's chocolate. However, some dogs are more sensitive, and any chocolate ingestion should be checked out by your vet or the pet poison control hotline (1-888-426-4435, expect a small fee to speak to a vet) to avoid illness or death.
Just like people, veterinarians have seen that dogs will crave chocolate after just a small taste. Most dogs have a very acute sense of smell and will hunt down any chocolate you may have stashed within their reach, so even a small amount might cause a dog to go hunting for more and gorge themselves on the secret stash without the owner's knowledge.
To complicate matters, theobromine has a half-life of 17 1/2 hours. If a dog eats 100 milligrams of chocolate, in 17 1/2 hours there is 50 milligrams of chocolate left in their system. In another 17 1/2 hours, there will be 25 milligrams left, and so on and so forth. So the chocolate never really leaves the system. If that same dog eats a small amount of chocolate every day, it will eventually reach a toxic level, so even a dog who ingests a non-toxic level should not be given the chance to increase that amount.
If your dog eats an unknown amount of chocolate, contact your vet immediately! Chocolate will cause excitability, irritability, restlessness, and increased heart rate. It has been known to cause vomiting, diarrhea, seizures and other complications that could lead to a heart attack or coma. The first few hours are the most critical to get rid of the chocolate before it absorbs into the dog's bloodstream. Vomiting can be induced in the first couple of hours. Your vet may also recommend a slurry of activated charcoal to absorb the theobromine before it can cause any serious affects. If serious neurological or cardiovascular symptoms start to appear, your vet may recommend an anticonvulsant to stop seizures, or other treatments like medications, oxygen, or fluids to protect the dog's heart.
Owning a dog doesn't mean you need to deprive yourself of your favorite sweets. It does mean that you need to be conscious of the effects they have on your animals. Just as you need to childproof your home so a child doesn't swallow medications or poisons, you should also dog-proof things that are toxic to dogs. Locking up that extra Halloween candy could save your dog's life!