Some are. Here are a couple links to lists of plants that are poisonous to pets: http://www.torontohumanesociety.com/caringforPet/poisonplants.html#T http://www.hsus.org/pets/pet_care/p...ousehold_dangers/common_poisonous_plants.html
Ilex verticillata? This is called winterberry, commonly planted. Or maybe you are asking about common snowberry (Symphoricapos albus). "Further Information Required", if Eric's links don't hit it.