Chocolate: Sweet and Poisonous

Chocolate sweet and poisonousChocolate … sweet chocolate. Some of us like it occasionally as a treat; others have a craving to eat chocolate every day. Some of us have just one favorite chocolate; others have a palette of favorites.  Some of us like plain chocolate; others like it as component of cakes and beverages. Although we have different tastes, it is hard to find a pet owner who does not like chocolate.

And because we like our pets, we want to share good things with them.

But chocolate is one of the things we should NOT share with our pets. It is toxic to dogs and could even lead to death.

Why can illness occur? Chocolate has large amounts of caffeine and a substance called  theobromine,  Both belong to a naturally occurring group of stimulants called methylxanthines that cause chocolate toxicosis in animals.  The substances affect the nervous system and  can increase heart rate, stimulate urination, cause vomiting and diarrhea, and make an animal restless.

So why can humans eat chocolate, but animals can’t?
Dogs cannot metabolize theobromine and caffeine as well as humans can. The substances accumulate in the animal’s body in an amount that can be toxic or even fatal.  For example, it will take a dog 17 ½ hours to metabolize and excrete just half of the  theobromine it has ingested. Also, if dogs should find chocolate,  they tend to eat much more than a person would. Theobromine poisoning can be caused by as little as 10 grams of baker’s chocolate for a smaller dog and 150 grams for an average-size dog.

What are toxic and lethal doses? Theobromine in a dose of 100-200 mg/kg can kill 50 percent of the dogs who have eaten chocolate. Symptoms of  chocolate intoxication (vomiting, diarrhea, increased water consumption and urination) can be seen after ingestion of 20 mg/kg.

How much theobromine is in chocolate? Theobromine concentration depends on the kind of  chocolate:

Type of chocolate

Theobromine concentration

Lethal dose (LD50)

Toxic dose

Baker’s chocolate

19 mg/g

5-10 g/kg

1 g/kg

Sweet dark

5-6 mg/g

16-40 g/kg

3 g/kg

Milk chocolate

2.3 mg/g

43-83 g/kg

8 g/kg

White chocolate, which isn’t really chocolate made from cacao beans, is not a significant source of theobromine and caffeine.

Prevention. The best way to cure chocolate toxicosis is prevention. If your dog has a source of chocolate, chances of poisoning are high. Teach your dog not to eat chocolate and make sure chocolate is not accessible.

But what if it happens?
If you find that your dog has eaten chocolate or if the animal shows any signs of chocolate intoxication such as restlessness, excessive thirst, urination and diarrhea, call your veterinarian immediately and tell him the amount and type of chocolate eaten, time the chocolate was eaten and size of the dog.

1.     If ingestion was recent, your veterinarian will instruct you how to induce vomiting or you will  bring your dog to a hospital to have vomiting induced (emesis). The animal will also be administered activated charcoal and eventually have his stomach irrigated (gastric levage).

2.     If more time has passed and the toxin is already absorbed, your vet will provide supportive therapy to help your dog’s body to detoxify.  Supportive therapy may include: drugs to control hyperexcitability and cardiac arrhythmias and intravenous fluids to increase urinary excretion of toxins.

The Animal Poison Control Center can offer advice (a $60 consultation fee may be applied to your credit card). 1-800-548-2423.

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