cigarettes, choclate (baking choclate), rasins and grapes, onions and many plants are poisionous to pets, and especially our small yorkies. I have a page with a listing of poisonious plants here
http://yorkieviews.com/toxicplants.htm and a page that lists a lot of other health hazards here
http://yorkieviews.com/dangers.htm
there are so many things that we take for granted that can be fatal to our pets.