Commercial chocolate is very toxic to dogs.
Therefore, only chocolate specifically manufactured and labeled “safe for dogs” should be given to them.
This is because normal chocolate contains chemicals called methylxanthines—specifically, theobromine and caffeine. And it is these chemicals that can prove fatal for dogs, even in small amounts.
However, the level of toxicity depends on the type of and amount of; chocolate ingested, plus the dog’s size. This means that one or two chocolate drops may affect one dog but not greatly affect another.
That being said, whenever a dog ingests the methylxanthines, specifically theobromine and caffeine, problems can occur. Baking chocolate and dark chocolate have the highest methylxanthines level, whilst white chocolate contains the lowest, but none are completely safe.
Small amounts can cause diarrhea, vomiting, excessive thirst, and urination. In contrast, a larger dose can cause hyperactivity, abnormal heart rhythm, tremors, hyperthermia (elevated body temperature), seizures, and even death.
Due to its varying degree of toxicity, chocolate remains high on the list of human foods dangerous to dogs.
If your dog does ingest human-grade chocolate, it may be wise to contact a veterinarian for advice.