Dear Dr. Mirodone,
Is chocolate bad for dogs, and if so, how much would my dog, who is 20lbs, need to eat to get sick?
This is a great question to ask right before Halloween! It is true that cocoa can be toxic to dogs, even at small doses. Cocoa contains the chemicals caffeine and theobromine, both of which can have adverse effects in dogs. It is the theobromine, however, that veterinarians are most concerned about.
The degree of toxicity is directly proportional with the concentration of cocoa in the chocolate. The darker and more bitter the chocolate, the more dangerous it is to our pets. Cooking or baking chocolate and high quality dark chocolate are the most concentrated in cocoa, and therefore the most toxic. Baking chocolate contains 390 mg of theobromine per ounce. Semi-sweet chocolate contains 150 mg per ounce, and milk chocolate contains 44 mg per ounce. White chocolate barely poses any threat of poisoning with only 0.25 mg per ounce of chocolate.
The toxic dose of theobromine is 9-18 mg per pound in the dog. For a 20-pound dog, that means that if he ingests 180 mg (approximately ½ an ounce of baker’s chocolate) of theobromine, he will have mild signs, like vomiting and diarrhea. If he ingests 360 mg of theobromine (approximately 1 ounce of baker’s chocolate), he could have very severe signs of chocolate toxicity.
With moderate doses of toxicity, the most commonly witnessed signs are vomiting and diarrhea, increased thirst, panting and excessive urination. With higher doses, we see restlessness, a racing heart rate, tremors and occasionally seizures. Seldom, with large amounts of high quality dark or baking chocolate, sudden death from cardiac arrest may occur, especially in dogs with preexisting heart disease. It can take hours for the symptoms to occur, and a lot longer for the toxin to be eliminated from the system.
Time is of essence for treatment of chocolate poisoning. Upon ingestion, call your veterinarian immediately. They will want to know what kind, and how much chocolate your pet ate.
They will decide if the dose is toxic and if your pet needs to be seen.
The first step is to induce vomiting. Hopefully the ingestion was recent and all or most of the chocolate can be removed from the stomach. Activated charcoal may also be administered to reduce the continued reabsorption and recirculation of theobromine.
In severe cases, it is common to provide supportive treatments, such as intravenous fluid therapy to help dilute the toxin and promote its excretion. All affected dogs should be closely monitored for any sins of agitation, vomiting, diarrhea, nervousness, irregular heart rhythm, and high blood pressure.
As prevention is the best cure, just keep tasty temptations out of reach, and Halloween will be enjoyed by all.
Dr. Olivia Mirodone is a veterinarian at Westgate Pet Clinic in Linden Hills. This column rotates among vets at Westgate. Email your pet questions to firstname.lastname@example.org.