For a dog, the smell of chocolate is almost as tempting as the smell of a big juicy steak. That's why you may find your dog ripping into a box of wrapped chocolates under the Christmas tree or nabbing a baker's chocolate from the kitchen counter.

Although he loves it, chocolate doesn't agree with your dog's system. That's because it contains caffeine and a related chemical called theobromine. Both of these are stimulants that raise your dog's heart rate-occassionally to the point of being fatal. Fortunately, most dogs who overdose on chocolate just get an upset stomach, which may be accompanied by vomiting and diarrhea.

The amount of chocolate that can cause death depends on your dog's size and the kind of chocolate he steals. With baking chocolate, half to one ounce can cause death in small dogs such as Chihuahuas and Toy Poodles. In medium-sized dogs such as Cocker Spaniels and Dachshunds, the amount is two to three ounces. In larger dogs, such as Collies and Labrador Retrievers, the amount is four to eight ounces.

With milk chocolate, four to ten ounces may cause death in small dogs; one to one and a half pounds in medium sized dogs; and two to four and a half pounds in large dogs.