Chocolate is toxic to dogs because it contains a chemical called theobromine, as well as caffeine. Dogs cannot metabolize these chemicals as well as humans, which allows these toxic compounds to build up in their systems and cause clinical signs associated with chocolate toxicity. The amount of methylxanthine, which includes theobromine and caffeine, varies within each type of chocolate, and the risk of your dog becoming sick from ingesting chocolate depends on the type and amount of chocolate consumed and your dog’s weight. Here are some key points to keep in mind:

• All types of chocolate can be toxic for dogs, but bakers chocolate and cocoa are considered to be the most toxic, followed by dark chocolate, semisweet chocolate, and milk chocolate.
• Even if the amount ingested is not a toxicity concern, dogs can still become ill from the fat and sugar in chocolate, which can cause pancreatitis in severe cases or in dogs that have more sensitive stomachs.
• The amount of chocolate a dog can eat without showing symptoms varies drastically with their weight. For example, a medium-sized dog weighing 50 pounds would only need to eat 1 ounce of bakers chocolate, or 9 ounces of milk chocolate, to potentially show signs of poisoning.
• Other ingredients that can be found in chocolate bars and other goodies, like raisins, walnuts, macadamia nuts, and caffeine, are also toxic to dogs.
• If you suspect your dog has eaten chocolate, you should monitor them closely and seek veterinary attention if they show any symptoms like a fast heart rate, vomiting, or tremors. Treatment depends on the dogs clinical signs, and they may need to be hospitalized to receive support in the form of intravenous fluid therapy, anti-nausea or anti-diarrhea medications, anti-seizure medications, etc.