Why is chocolate poisonous to dogs?

Wikipedia weighs in

Short answer: It’s a chemical called theobromine that many mammals can’t metabolize, so it ends up floating around the blood stream for too long. For whatever reason, humans and some other apes metabolize fast enough that we’re just fine.

Not all dogs react to it, though. But there are a bunch of things that people can eat that dogs can’t. Like aspirin and grapes.

thank goodness for our special metabolisms. i love chocolate.