By Stephen T. Sinatra, M.D., F.A.C.C., F.A.C.N., C.N.S., C.B.T.
As any dog owner knows all too well, these furry companions just love getting their noses in (and mouths on) anything they can get a hold of. Fortunately, most of the food and other “stuff” (bugs…newspapers…very small socks) they end up ingesting goes through them without causing too much trouble.
But there are a few key foods every dog owner needs to know about because they can be really harmful—even fatal—if eaten. Chocolate tops that list. So it’s especially important around Halloween and the winter holidays to be extra careful with what your pups could potentially get into. With chocolate gifts and holiday cookies and cakes everywhere, not to mention plastic pumpkins filled with candy, you have to be on high alert.
A trusted veterinarian colleague tells me that she treats most dogs for chocolate toxicity between late October and December – that around this time, food-driven doggies are notorious for quickly swiping chocolate candies from kitchen counters, as well as out of shopping bags left on the floor. One of her patients actually opened the fridge and woofed down an entire chocolate cake!
Why Is Chocolate Toxic to Dogs?
Chocolate comes from the cacao plant. The plant’s seeds contain a compound called theobromine, which is what gives chocolate (most notably the extra dark varieties) its bitter “bite.” The theobromine is also what makes chocolate so toxic to dogs.
Interestingly, in humans, theobromine poses no threat. Its half-life (the time it takes for the concentration of a substance to decrease by half) is two to three hours. This means we can quickly digest and excrete it before it causes us any harm.
In dogs, though, the absorption rate is extremely slow—with a half-life of approximately 17.5 hours. This means the compound stays in their system for a very long time, making them much more sensitive to its toxic effects. Pregnant dogs and nursing puppies are especially vulnerable, as theobromine will cross the placenta and get excreted into milk, and potentially affect unborn or nursing puppies.
Besides theobromine content, chocolate is also often mixed with other ingredients that are dangerous to dogs. My vet colleague once treated a dog who devoured chocolate covered coffee beans – after 36 hours of life-threatening symptoms due to the combined theobromine and caffeine toxicity, the dog made it through okay. She’s also treated a dog for theobromine and THC toxicity after – you guessed it – the dog downed some pot brownies.
Signs That Your Dog Ate Chocolate
Besides empty candy wrappers on the floor or a missing plate of bon-bons, it may be difficult to determine if Ruff, indeed, raided your chocolate stash. In multi-pet households where foil-wrapped candy is consumed, an X-ray can be useful for identifying the culprit before symptoms appear.
Signs of theobromine poisoning in dogs usually appear about two to six hours after consumption. At first, the dog usually acts extremely hyper, restless, and agitated. Increased thirst, vomiting, and drooling are also early signs.
Later symptoms may include:
- Racing heart (tachycardia and arrhythmia)
- High blood pressure
- Excessive panting
In severe cases, hyperthermia, low blood pressure, seizures, heart attack, heart failure, and/or death can occur. Even worse, because it takes so long for dogs to metabolize theobromine, symptoms can last for up to three days before subsiding.
How much chocolate does a dog have to eat to have a reaction? It varies depending on two factors – the type of chocolate, and the size/weight of the dog.
The darker (and more bitter) the chocolate, the more toxic it is. Dark and semi-sweet baker’s chocolate have higher cacao content, containing about 130 mg of theobromine per ounce (unsweetened has 400mg per ounce). By contrast, milk chocolate has 44-60 mg per ounce, and white chocolate contains only miniscule amounts.
Naturally, a large dog can consume far more chocolate than a small dog before suffering the ill effects. So if 50-lb Hazel gets into a bag of baker’s chocolate and eats about an ounce, she could get sick but probably won’t die. (She would have to eat up to 10 ounces of milk chocolate to experience symptoms.) But if 10-lb Rufus ate that same amount of dark chocolate, he would have a much, much higher risk of serious problems and death.
Lastly, I think it’s worth mentioning that even though milk chocolate is low in theobromine content, it is high in fat, and some dogs come down with pancreatitis after ingesting a good amount of it.
What to Do If Your Dog Eats Chocolate
If you suspect or know that your dog ate chocolate, call your veterinarian immediately. Based on your dog’s size, the amount he ate, and when he ate it, your vet may recommend monitoring him for signs of illness and to call back if symptoms or his condition worsens.
Your vet may even recommend trying to get your dog to throw up at home, especially if you are sure your dog ate the chocolate two or less hours ago.
It’s really not as hard as it sounds—and you probably already have what’s needed in your bathroom…good old 3% hydrogen peroxide (the kind you can buy at any drug store).
The dose is one teaspoon (five milliliters) for every 10 pounds of body weight. Do not use more than 45 ml total dose. Using a syringe, open your dog’s mouth wide and squirt it as far down his throat as you can to ensure it gets swallowed. (Your dog won’t be happy with you, but trust me, it’s better than the alternative!)
Hydrogen peroxide irritates the gastrointestinal tract and typically causes vomiting within 15 minutes. If it doesn’t, you can try a second dose. But if that doesn’t do the trick, call the vet.
All this being said, getting your dog to throw up at home can be risky – serious complications like aspiration and bradycardia can happen, and these are the kinds of reactions you want a vet there to treat. Safest bet is to, if possible, get your sick doggie to the vet in a timely manner.
Also, you should not use hydrogen peroxide if your dog is already throwing up, he is weak or lethargic, or if it has been more than two hours since he ate the chocolate. At that point, it’s likely already made its way to the small intestine so it can’t be eliminated via vomiting.
If it gets to that point, your veterinarian can monitor your dog to make sure he/she stays as stable as possible while the theobromine works its way out naturally. Depending on severity of symptoms, this may include intravenous fluids, medications to slow elevated heart rate or treat arrhythmias, and administration of activated charcoal, which traps toxins in the gut and blocks their absorption and reabsorption. (That’s right…as if this situation isn’t terrible enough, theobromine can be reabsorbed from the bladder wall, prolonging a dog’s symptoms even more. In addition to activated charcoal, IV fluids and frequent walks can promote frequent urination and defecation so that the toxin can be eliminated faster.)
Cats and Chocolate
As those of you with cats probably already suspect, chocolate toxicity is far more common in dogs than in cats. This is because cats lack taste receptors on their tongues for sweet things. This doesn’t stop some cat parents from trying to “treat” kitties to goodies us humans love, the consequences of which can be severe. Best bet is to treat cats instead to foods you know are good for them –like nutritious, single-ingredient treats that are free of additives, preservatives, artificial flavors or fillers. And while chocolate poses less of a natural threat to finicky felines, cat parents should still be wary of leaving chocolate out for curious kittens to sample.
Should your cat actually eat chocolate, the treatment is similar to dogs, except that your vet will use hydromorphone instead of hydrogen peroxide to get it out of her tummy. IV fluids, propanolol, and charcoal may also be used to mitigate damage.
Preventing Dogs from Eating Chocolate Is Your Best Bet
No dog owner wants to go through the anxiety, misery, and financial strain of caring for a sick pet—especially when it can be so easily prevented. So this Halloween, Christmas, and Hanukkah— all year round, really—make sure you store your sweet treats high up in a pantry or other closed off space that your dog can’t reach or access. Repeatedly discuss the importance of this with your kids and grandkids, too. If you have a particularly food-driven dog – like a Labrador – you may even want to consider putting a child-proof lock on your fridge. And be sure to have lots of healthy edibles on hand to treat your dog to – like 100 percent turkey heart, chicken breast, wild salmon or bison liver freeze dried treats!
And a final note—along with chocolate, the other foods that your dog should avoid eating are onions, garlic, grapes/raisins, macadamia nuts, and fruits with pits such as peaches and plums. Xylitol, an artificial sweetener found in many chewing gums and sugar-free foods is also a serious toxin for dogs, so be sure to read labels!
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- Plumb, Donald C. Plumb’s Veterinary Drug Handbook. 8th ed. 2015. pages 525-526.
- Brooks W. Xylitol poisoning in dogs. Veterinarypartner.vin.com, last reviewed July 16, 2018.
This blog has been reviewed and approved by veterinarian, Emily Wilkinson, DVM.
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