10 Poisonous Plants for Cats

#1 Lilies

Many types of lilies, including those commonly bought around the holidays, are toxic to cats. While all parts of the plant are deadly, the flowers are particularly potent, causing severe illness with just a nibble.

Lilies are the most dangerous plant for cats. Many different types of lilies (Lilium spp.) can make cats seriously ill, including Easter lilies, daylilies, Asiatic and Japanese lilies, stargazer lilies, tiger lilies, Western lilies, and wood lilies.

All parts of the lily plant are deadly to cats, but the flowers are especially toxic. Cats need only consume a tiny amount of plant material to suffer severe effects (vomiting, lack of appetite, lethargy, kidney failure, and death). Lilies and cats simply don’t mix.

It’s best to ban this flower from your home and yard if you have cats.

#2 Autumn Crocus 

The autumn crocus is extremely toxic to cats. Especially if your cat goes outside, it’s important to ensure that he can’t get a nibble of this common outdoor plant.

The autumn crocus (Colchicum autumnale), sometimes called the meadow saffron or naked lady is extremely toxic to cats (and dogs and horses, to a lesser degree) due to its alkaloid colchicine content. Cats that ingest autumn crocus might start acting sick right away or days later.

Symptoms of autumn crocus poisoning in cats may include drooling, vomiting, bloody diarrhea, breathing difficulties, seizures, and death. This outdoor plant should be avoided for a cat-owning household, especially if your cats go outside. 

#3 Azaleas and Rhododendrons 

Eating a tiny amount of azaleas or rhododendrons could make a cat seriously ill.

Azaleas and rhododendrons (Rhododendron spp.) contain poisonous compounds called grayanotoxins that are highly toxic to cats. A cat only needs to consume a minuscule amount of an azalea or rhododendron to become poisoned. Signs of grayanotoxin poisoning in cats may include drooling, vomiting, diarrhea, lack of appetite, weakness, tremors, seizures, coma, and death.

#4 Oleander 

All parts of the oleander plant are toxic to cats, causing serious illness if ingested.

Oleander (Nerium oleander) contains cardiac glycoside toxins, which can cause drooling, vomiting, diarrhea, incoordination, tremors, seizures, and death. All parts of the oleander plant are poisonous to cats. 

#5 Cyclamen 

Every part of the cyclamen or Persian violet plant can poison your cat. The tubers and roots are particularly dangerous.

Cyclamen (Cyclamen spp.) is a common houseplant that’s sold under the name Persian violet. Although the parts that are the most poisonous are below ground (the tubers and roots) all parts of the cyclamen contain saponins, the compound that is toxic to cats. The larger amount the cat swallows, the worse the symptoms will be.

Small amounts of cyclamen may only cause drooling and stomach upset, but large amounts can cause severe symptoms up to and including seizures and death. 

#6 Daffodils/Narcissus 

Thanks to an alkaloid called lycorine, daffodils are toxic to cats.

Daffodils (also called jonquil or Narcissus), contain lycorine, which typically causes drooling, vomiting, diarrhea and abdominal pain in cats. Rarely, low blood pressure, breathing difficulties and convulsions may be seen. Although all parts of the daffodil plant contain lycorine, the bulbs are the most dangerous part of the plant. 

#7 Marijuana

Cats may exhibit symptoms immediately or up to 12 hours after ingesting marijuana.

(Cannabis sativa), commonly known as pot or weed, is toxic to cats. The toxic compound found in marijuana is tetrahydrocannabinol, better known as THC. Cats may become poisoned when ingesting the plant itself, or ingesting foods containing concentrated marijuana like baked goods or pot butter.

Signs of marijuana toxicity in cats include dilated pupils or glassy-looking eyes, sedation/lethargy, difficulty walking, vomiting, incoordination, either sleepiness or excitation, excessive salivation, excessive vocalization low blood pressure, low or high body temperature, tremors, seizures, coma and rarely, death.

Cats may exhibit symptoms immediately or up to 12 hours after ingesting marijuana. 

#8 Tulips

Tulips can cause drooling, vomiting, diarrhea, depression, and tremors

(Tulipa spp.) contain tulipalin A and tulipalin B, which cause drooling, vomiting, diarrhea, depression and tremors. The toxic compounds are found in all parts of the tulip plant, although the bulbs are the most dangerous. 

Similar to tulips, hyacinths (Hyacinthus orientalis) can cause drooling, vomiting, diarrhea, depression, and tremors. Also similar to tulips, the toxic compounds are found in all parts of the hyacinth plant, but the bulbs are the most toxic.

#9 Dieffenbachia

Although the dieffenbachia plant is usually not lethal, these symptoms are painful and extremely unpleasant for cats.

(Dieffenbachia spp.), also known as dumb cane or exotica perfection, contains insoluble calcium oxalate crystals, which cause oral irritation in cats (drooling, difficulty swallowing and vomiting).

Although the dieffenbachia plant is usually not lethal, these symptoms are painful and extremely unpleasant for cats.

#10 Kalanchoe

Kalanchoe poisoning typically cause drooling, vomiting and diarrhea in cats.

(Kalanchoe spp.), also known as mother-in-law plant, contains poisonous compounds called bufadienolides, which typically cause drooling, vomiting and diarrhea in cats.

Some other common plants toxic to cats include amaryllis, calla lily, castor bean, chrysanthemum, foxglove, hydrangea, various species of ivy, lily of the valley, mistletoe, morning glory, peace lily, philodendron, poinsettia, pothos, sago palm, schefflera, and yew.