Many house and garden variety plants contain chemicals that if ingested in sufficient quantities, can produce toxic effects in dogs and cats. Severe or lethal poisonings are rare; however, many plant toxins can cause discomfort. Listed below are some plant toxins that curious pets should be kept away from.

Plants that affect the stomach and Intestines;
Azaleas (leaves)
Bulbs (Tulip, daffodil, amaryllis, iris)
Castor beans (seeds)
Precatory beans (seeds)
English Ivy (berries)
Mistletoe (berries)
Nightshade (berries)
Walnuts (hulls from around the nut)
Pointsettis (sap)
Snow on the Mountain (sap)

Plants that cause irritation of the mouth and throat;
Dieffenbachachia or Dumb Cane
Cut-Leaf Philodendron
Philodendron
Alocasis or elephant Ears
Calis Lily

Plants that affect the blood and circulation;
Oleander (Extremely toxic)
Yellow Glove or Yellow-Be-Still Tree
Foxglove
Choke Cherry (pits and bark)