I visited the Humaine Society's website and found some interesting information about poisonous plants in the home garden (poisonous to humans, dogs, and cats).  Although there is no discussion about what (how much) constitutes a toxic dose, the information is still interesting.  The buttons on the left should appeal to animal lovers.

www.hsus.org/pets/pet_care/protect_your_pet_from_common_household_dangers/common_poisonous_plants.html

Enjoy, Web Administrator