We love chocolate so much that the phrase "dog death by chocolate" might look humorous. But the sweet stuff can literally mean curtains for your dog. 

If your sweet-toothed canine has helped himself to a sweet treat, it could mean a stomachache or worse, says Dr. Melanie Landis, a veterinarian at the College of Veterinary Medicine and Biomedical Sciences, Texas A&M University. 

Although chocolate may be one of your favorite indulgences, it shouldn't be one of your dog. "Chocolate contains a chemical called theobromine which is toxic to dogs," says Landis. "If ingested in large quantities, theobromine can stimulate the nervous system and cause irregularities in heart function." 

When theobromine levels are considered, not all chocolates are created equal. Different types of chocolate contain varying concentrations of theobromine. "Dark and baking chocolates have the highest concentrations and should be strictly avoided," warns Landis. "Even in small amounts, these chocolates can be toxic." 

With any cocoa concoction in his system, your dog may display hyperactive behavior much like you do after losing count of how many chocolate peanut butter cups you've eaten, says Landis.