Baker's chocolate is the type that you need to worry about. I made a frantic call to the emergency vet one night after my Heidi ate quite a bit of chocolate frosting. The vet on call said to keep an eye on her, but no need to rush her in if it wasn't baker's chocolate. She was miserable all night (ugh- doggie gas) but she survived just fine.

Heidi did have to have vomitting induced as a puppy when she ate an entire Kit Kat bar and WRAPPER! The vet was more worried about the foil wrapper than the kit kat. She also had a marble surgically removed, that came with a $400 bill.