Chocolate contains theobromine, a compound in the same family as caffeine, and theophylline (an asthma drug). In certain quantities, theobromine is toxic to dogs.
In general, the minimum toxic theobromine dose in dogs ranges from 46 to 68 mg/lb.
Half the dogs that consume 114 to 228 mg/lb or greater of theobromine will die.
Lots of things can play a role in whether your dog will have a toxic reaction including the amount of chocolate your dog ate, your dog’s size, and whether your dog happens to be extra-sensitive to theobromine. One of the most important things in chocolate toxicity is the kind of chocolate your dog ate. For instance:
Milk chocolate contains 44mg of theobromine per oz. (704 mg theobromine/lb milk chocolate)
Semisweet chocolate chips contains 150mg/oz. (2400 mg theobromine/lb semisweet chocolate)
Baking chocolate contains 390mg/oz. (6240 mg theobromine/lb baking chocolate)
Please don’t leave your dog with access to consume chocolates.