Chocolate contains two substances that are toxic to dogs: theobromine and caffeine. The amounts vary with the type of chocolate. Baking chocolate contains the most, followed by dark chocolate, and milk chocolate. White chocolate contains the least amount of theobromine and caffeine.
Signs can vary when a dog eats chocolate, although not every dog will develop toxicity. Watch for gastrointestinal upset (diarrhea and vomiting), nervous system disorders (hyperactivity, tremors, seizures), and cardiovascular changes (arrhythmias). Your veterinarian can calculate the amount of toxic substance consumed, and determine if treatment is needed. Treatments can be as simple as subcutaneous fluids, stomach protectants, and a bland diet. More difficult cases might call for hospitalization, intravenous fluids, and anti-convulsants.
Variables can involve the type of chocolate, the amount eaten, and the weight of the dog. Call us when you think your dog has eaten chocolate and we'll be glad to consult. At the clinic and in our homes, we keep all foods containing chocolate out of reach of our dogs, and well within our own reach instead!