The ASPCA has compiled a list of the 17 most poisonous plants to help cats avoid.
1. Yuri
Lilies are considered highly toxic to cats. Many types of lilies, including tiger lilies, Asiatic lilies, Japanese show lilies, Easter lilies, stargazer lilies, and Casablanca lilies, can cause kidney failure in cats. Although the toxic components have yet to be identified, it is clear that even ingesting very small amounts of lily plants can cause severe kidney damage.
2. Marijuana
When pets ingest Cannabis Sativa, even if they don't inhale it, it can cause central nervous system depression, loss of coordination, vomiting, diarrhea, drooling, rapid heart rate, and even seizures and coma.
3. Sago palm
All parts of the cycad are poisonous, but the seeds or “nuts” contain the most toxins. Ingesting just one or two seeds can cause very serious effects, including vomiting, diarrhea, depression, seizures and liver failure.
4. Tulip/daffodil bulbs
Tulip and daffodil bulbs contain toxins that can cause severe gastrointestinal irritation, drooling, loss of appetite, central nervous system depression, convulsions and cardiac abnormalities.
5. Azalea
Rhododendron plants contain a substance called grayantoxin, which can cause vomiting, drooling, diarrhea, weakness and central nervous system depression in animals. Severe grayantoxin poisoning can ultimately lead to coma and death from cardiovascular collapse.
6. Oleander
All parts of Nerium oleander are considered toxic because they contain cardiac glycosides that can cause serious effects including gastrointestinal tract inflammation, cardiac abnormalities, hypothermia, and even death.
7. Castor beans
The poison in castor beans is ricin, a highly toxic protein that causes severe abdominal pain, drooling, vomiting, diarrhea, excessive thirst, weakness and loss of appetite. Severe poisoning can lead to dehydration, muscle spasms, tremors, seizures, coma and death.
8. Cyclamen
Cyclamen species contain cyclamine, with the highest concentrations of this toxic compound usually found in the roots of the plant. Ingestion of cyclamen can cause severe gastroenteritis, including severe vomiting. Some deaths have also been reported.
9. Kalanchoe
This plant contains compounds that are gastrointestinal irritants and cardiac toxic, which can severely affect heart rhythm and rate.
10. Yew
It contains a toxic compound called taxine that causes central nervous system effects such as tremors, loss of coordination and difficulty breathing, as well as severe gastroenteritis, heart failure and death.
11. Amaryllis
These common garden plants are popular during the holidays and contain toxins that can cause vomiting, depression, diarrhea, abdominal pain, excessive salivation, loss of appetite and tremors.
12. Autumn Crocuses
If pets ingest Colchicum autumnale, it can cause oral inflammation, bloody vomiting, diarrhea, shock, multiple organ damage, and bone marrow suppression.
13. Chrysanthemum
These popular flowers belong to the Asteraceae family and contain pyrethrins, which can cause gastrointestinal problems like drooling, vomiting and diarrhea if ingested. Also, consuming large amounts of any part of the plant can cause depression and loss of coordination.
14. English Ivy
Hedera helix (also known as branching ivy, glacier ivy, needlepoint ivy, sweetheart ivy and California ivy) contains triterpenoid saponins that can cause vomiting, abdominal pain, excessive salivation and diarrhea if ingested by pets.
15. Peace Lily (aka Mauna Loa Peace Lily)
Spathiphyllum contains calcium oxalate crystals which can cause oral irritation, excessive drooling, vomiting, difficulty swallowing, and severe burning and irritation of the mouth, lips, and tongue in pets who ingest it.
16. Pothos
Pothos (both Scindapsus and Epipremnum) are in the Araceae family. This popular household plant can cause significant mechanical irritation and swelling in oral tissues and other parts of the digestive tract if chewed or ingested.
17. Schefflera
Schefflera and Brassica actinophylla contain calcium oxalate crystals which, if ingested by your pet, can cause oral irritation, excessive drooling, vomiting, difficulty swallowing, and severe burning and irritation of the mouth, lips, and tongue.
This article was updated in conjunction with AI technology and then fact-checked and edited by HowStuffWorks editors.