Did you know that during the week of Easter, chocolate poisonings calls to the Pet Poison Helpline increase by nearly 200 percent? Over the past year, more than 1,100 calls to Pet Poison Helpline, an animal poison control center based out of Minneapolis, involved chocolate exposure, with 98 percent of them involving dogs. (Apparently, cats have a very discriminating palate!)
With all those Easter bunnies around, it’s no surprise that dogs have access to chocolate during this time of the year. Actually, it seems like any time there’s a holiday (e.g., Halloween, Valentine's, Christmas, etc.), chocolate abounds. It appears America is obsessed with combining holiday enjoyment with chocolate. And don’t forget about other sources of chocolate around the house: chocolate liquor, chewable chocolate flavored multi-vitamins, baked goods, or chocolate-covered espresso beans (which are even more poisonous because of the extra caffeine in the beans!).
Most pet owners are aware that chocolate is poisonous, but keep in mind that it’s the amount and type of chocolate that makes it poisonous. While the occasional chocolate chip in one cookie isn’t an issue, certain types of chocolate are very toxic to dogs.
In general, the darker and more bitter the chocolate, the greater the danger. Baker’s chocolate and dark chocolate pose the biggest problem.
For example, a 50-pound dog can be sickened by ingesting only one ounce of Baker’s chocolate! On the other hand, it may take up to eight ounces (half a pound) of milk chocolate to cause poisoning in that same sized dog. For white chocolate, it would take over 100 pounds to cause chocolate poisoning in a 50-pound dog; that said, he’d also get really sick from all that fat and sugar!
With chocolate, the chemical toxicity is due to methylxanthines (a relative of caffeine). The results are vomiting, diarrhea, hyperactivity, lethargy, agitation, increased thirst, an abnormal heart rhythm or racing heart rate, seizures, and possibly death.
Clinical signs of poisoning can be seen with as low as 20 mg/kg of theobromine. Amounts greater than 40 mg/kg of theobromine can result in cardiotoxicity — in other words, it’s poisonous to the heart and can result in a racing heart rate and heart arrhythmias. Amounts greater than 60 mg/kg of theobromine can result in neurotoxicity — in other words, it’s poisonous to the nervous system and can result in tremors, seizures, or even death.
A few years ago, I had my first chocolate fatality: a young, adorable Pug. He ate one whole bag (12 ounces) of semi-sweet chocolate chips, and the pet owner didn’t bring him in until his signs were severe (one day later). The pug had chocolate fluid coming out of his nostrils from severe aspiration pneumonia. The poor guy had been vomiting so much, he had inhaled the chocolate into his lungs.
This could have all been avoided had the pet owner brought the dog in immediately, before he even developed any clinical signs.
Remember, with any poisoning, it’s always cheaper, less invasive, and has a better prognosis/outcome if you treat early. Once your pet has already developed clinical signs and is affected by the poison, it makes for a much more expensive veterinary visit!
Treatment includes inducing vomiting (depending on when the chocolate was ingested), giving activated charcoal several times (to bind the chocolate from the stomach and intestines), anti-vomiting medication, and potentially, IV fluids and heart medication (e.g., beta-blockers). So, avoid this problem by pet-proofing your house adequately instead, and keeping your chocolate stash elevated and out of reach. That way you can avoid that spring-time visit to your emergency vet at 1 a.m.
You can see from the chart below how much theobromine is in different types of chocolate. If you’re mathematically challenged during stressful situations (e.g., your dog just got poisoned!), doing advanced math might be harder than you think.
Source: Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Toxicology, 1st Ed., 2010; Small Animal Toxicology, 2nd ed., 2006
When in doubt, you can always call your veterinarian or Pet Poison Helpline at 1-855-213-6680 to determine if the amount of chocolate ingested was poisonous or not. You can also use the petMD Chocolate Toxicity Meter.
Dr. Justine Lee