The other toxic ingredient in candies is an alkaloid called theobromine. Theobromine, when ingested by dogs, is an indigestible ingredient that stimulates the central nervous system, and cardiovascular system, and causes an increase in blood pressure. Dogs can’t metabolize theobromine as quickly as humans can. If your dog has ingested theobromine, toxic levels will show up as diarrhea, excessive panting, excessive urination, muscle twitching, vomiting, hyperactive behavior, dehydration, and seizures. Older dogs and smaller dogs tend to have more serious issues when theobromine is ingested. Although all chocolate is toxic for dogs dark chocolate and baker’s quality chocolate have the highest content of cocoa and therefore have higher contents of theobromine and can cause way worse reactions than chocolate such as milk chocolate. A tiny square of dark chocolate is just as harmful as 23 wrapped chocolate drops. Cocoa powder contains 16 times more theobromine per ounce than most common chocolate candies.