*Please note that most most animals have good instincts on what not to eat and that large qualities of most houseplants have to be ingested in order for it to have serious effects on an animal's health.
If you find that your pet is prone to crewing on houseplants, consider planting a 'cat grass' planter with oats, barley or even lawn seed, to satisfy their needs in a safe way.
Apple Tree: Stems, leaves, and seeds.
Apricot: Keep dogs, cats, and horses away from apricot stems, leaves, and seeds.
Autumn Crocus (Colchicum autumnale)
Castor Bean (Ricinus): This plant is highly toxic, but only rarely ingested by pets.
English Ivy (Hedera helix)
Lilies (Lilium): leaves, pollen and flowers, especially to cats.
Lily of the Valley
Oleander (Nerium oleander)
Peace Lily (Spathiphyllum)
Sego Palm (Cycas revoluta)
Tulips and Narcissus bulbs (Tulipa and Narcissus)
Burros tail succulents
Cast iron plants