13 Popular but Toxic Plants for Cats

It’s Poison Prevention Week, so we’re looking at common pet poisons found around the home. In this article, we’re looking at ornamental plants that are poisonous to cats. Below is our roundup of the 13 most toxic plants for cats. See also our top 10 cat poisons roundup.

Ornamental plants can be found in homes across the nation. They help reduce stress, promote well-being and improve air quality. Cat also love to chew on them!

Keeping house plants as a cat owner can be difficult. No matter where you position the plants, it seems like the cats can reach them. If they aren’t knocking the vase off the shelf, then they are trying to nibble at the plant or lap the water. Unfortunately, some popular ornamental plants are toxic when ingested. Some are more toxic than others. Some of the most commonly reported toxic plants for cats are listed below.

Allium

Allium spp. – The most recognised members of the Allium genus are onions, garlic, leeks, chives and shallots. Allium species contain organosulphur compounds which are toxic to cats and other animal species. As these plants are often used in cooking, be aware of waste left during meal preparation.

Gastrointestinal distress, lethargy, excessive thirst and anaemia have been reported in cats.

Autumn Crocus

Colchicum autumnale – Although this species is known to be toxic, it is still a popular ornamental plant in temperate regions. This plant contains a toxic compound called colchicine, which prevents DNA synthesis.

Initial gastrointestinal symptoms appear after a few hours. After around 24 hours, heart failure, arrhythmias, kidney failure, liver damage and respiratory distress can develop.

Castor Bean

Ricinus communis – The castor bean is a flowering plant mainly found in Europe. All parts of this plant are toxic, particularly the seeds. The seeds (‘beans’) of this plant contain ricin, which is released when a seed is broken or chewed.

Ricin is highly toxic and causes animal cells to die. Only a few seeds are needed to cause a fatal poisoning. Bloody diarrhoea, abdominal pain, weakness, trembling and incoordination are symptoms of ricin poisoning.

Daffodils

Narcissus spp. – The most toxic part of a daffodil is the bulb. Cats are unlikely to uproot the flower and eat the bulb, so severe poisoning in cats is rare. Daffodils contain toxic alkaloids such as galanthamine and lycorine.

The toxic daffodil alkaloids cause vomiting and diarrhoea, abdominal pain or anorexia. They may cause heart problems in large enough doses.

Jimson Weed

Datura stramonium – Considered a weed, this plant may be grown as an ornamental plant in Europe. The toxic compounds in this plant are tropane alkaloids which can be found in all parts, especially the seeds.

Symptoms of poisoning can appear quickly and include increased heart rate, dilated pupils, dry mouth, incoordination, convulsions and even coma.

Lilies

Lilium spp. – Potentially the most toxic plant on this list due to the popularity of lilies as ornamental plants. Cats are highly sensitive to the unknown toxic lily compound, which causes severe kidney damage.

Initial symptoms of poisoning include vomiting, inappetence, lethargy and anorexia. Severe kidney failure can be fatal in days if not treated. Read more about lily toxicity.

Mistletoe

Viscum album – Mistletoe is a popular decoration around the Christmas festive period. If you keep real mistletoe over Christmas, be aware that the leaves and stem contain alkaloids, glycosides and viscotoxins.

Symptoms of poisoning include vomiting and diarrhoea, but the viscotoxins can also affect the heart and nervous system.

Oleander

Nerium oleander – Oleander is a common ornamental shrub. All parts of the plant are considered toxic. Toxicity occurs as a result of cardiac glycosides that cause damage to the cardiovascular and gastrointestinal systems. Symptoms of poisoning include vomiting, diarrhoea and tremors or seizures in more severe cases.

The leaves are particularly toxic and only a few need to be consumed for a lethal dose. Cases of oleander poisoning are low, despite its high toxicity. Treatment of oleander toxicity has good results.

Poinsettia

Euphorbia pulcherrima – Poinsettia is another common plant found around the Christmas period. Toxic diterpene esters are found in the milky sap of the stem and buds. Consumption of the toxic sap typically causes mouth irritation, salivation, vomiting and occasionally diarrhoea.

The toxic sap can also cause irritation to the eyes and skin. Washing the affected area with warm water can help.

Rhododendron

Rhododendron spp. –  Rhododendrons and azaleas are flowing shrubs usually grown outdoors. All parts of this plant are toxic to animal species, including the cat. Rhododendron species contain grayanotoxins which affect the nervous system.

Gastrointestinal, nervous, cardiac and respiratory distress can occur following consumption. Cat owners should be aware of these shrubs that may be growing in their local area as they are widely popular.

Sago Palm

Cycas revoluta – A popular ornamental plant that is native to Japan. All parts of the plant are toxic, particularly the seeds. The toxin found in this plant is glycoside cycasin.

This toxin can cause gastrointestinal distress, liver damage and neurological issues. Mortality is high in cases where this plant has been consumed.

Tulips

Tulipa ibrido – A well-known and popular ornamental plant found in garden and boquets, tulips come in many colours. Similar to daffodils, the bulbs contain toxic alkaloids that affect the digestive system.

Cats are unlikey to uproot the flower, making the risk of toxicity low.

There are many more toxic plants for cats…

Although this list provides some of the more popular ornamental toxic plants for cats, there are many more. Some are more of a toxic risk than others. If you are have or are getting house plants, first research to see if they are poisonous if ingested. For a more complete list of toxic plants for cats see this article.

Further reading:

Cortinovis, C. and Caloni, F. (2013). Epidemiology of intoxication of domestic animals by plants in Europe. The Veterinary Journal, 197(2), pp.163-168.

Severino, L. (2009). Toxic plants and companion animals. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 4(008).