“They just can’t break it down asw fast as humans and so therefore, when they consume it, it can cause illness,” Mike Tropper, president of the American Veterinary Medical Association, tells Mental Floss. The toxin effects can a mild upset stomach to seizures, heart failure, and even death. If your dog does eat chocolate, they may get thirsty, have diarrhoea, and become hyperactive and shivery. While cats are even to theobromine, they ‘re less chocolate in the first place.