It's more accurate to say that theobromine is poisonous to dogs: 100mg to 1kg of body weight.

Which is why my shepherd can filch the occasional candy bar and not die. One candy bar - annoying (to me) but not fatal. A pound of bakers chocolate and she'd be in doggy heaven.

Yet another fun fact: if your dog eats something bad like a hotdog or chocolate, pour some hydrogen peroxide down its throat. It'll make the dog puke up the bad bits. Obviously, do this outside or in an area you can easily clean up.