Why is Chocolate Bad for Dogs?

Why is chocolate bad for dogs, anyway?

It turns out that it all comes down to biochemistry. The problem with dogs and chocolate stems from two facts:

Dogs love chocolate because they have a sweet tooth.
Chocolate contains a compound called theobromine.

Theobromine is a chemical compound that is metabolized (i.e. changed) into a chemical called xanthine in the dog’s liver.

And xanthine is bad for dogs. Why? Because xanthine interferes with very important phosphodiesterase inhibitors (a special class of cell enzymes), leading to:

increased heart rate
increased central nervous system activity

Left unchecked, this increased heart rate or the overload of activity in a dog’s brain can be deadly.

Left unchecked the increased heart rate or the overload of activity in a dog’s brain can be deadly.

The excess vomiting, urination, and diarrhea of a dog after eating chocolate is actually a safety mechanism to try and purge the dog’s body of the toxic buildup.

This also helps explain how coffee is bad for dogs, since the biological breakdown of caffeine produces theobromine as well.

No tastes for you!

You might be wondering: why is chocolate bad for dogs, but not for humans?

Well, believe it or not, theobromine, and therefore chocolate, is actually toxic to humans as well. The major difference between dogs and humans is that humans can metabolize or breakdown the theobromine at a much higher rate. To put this in perspective, a dog weighing 17 pounds needs to consume about 1 pound of milk chocolate to reach a lethal dose.

To put this in perspective, a dog weighing 17 pounds needs to consume about 1 pound of milk chocolate to reach a lethal dose.

Doing some rough math, say a human weighs about 150 pounds. Considering the fact that humans are 500% more tolerant to theobromine than a dog, one would need to consume about 44 pounds of chocolate in 24 hours to reach lethal levels. (Note: this calculation also assumes you can eat all of the chocolate without vomiting!)

For more, find out what happened when one owner’s dog ate chocolate—it has a happy ending, we promise.

In conclusion, when it comes to dogs and chocolate, you’re better safe than sorry. Dog owners and dog sitters shouldn’t let those pups have even a nibble. As for yourself—go ahead and nosh on that candy bar. Just don’t eat a hundred of them.