Is Shamrock Plant (Oxalis) Toxic to Cats? A Vet Explains

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  • What is oxalis?

    • Family: Oxalidaceae
    • Botanical name: Oxalis spp.
    • Common names: Shamrock plant, Wood sorrel, False shamrock,  Wood plant, Good luck plant, Sorrel, Love plant
    • Plant type: Perennial
    • Toxicity: Toxic to cats
    • Toxic parts: All parts
    • Severity: Moderate
    • Toxic properties: Oxalic acid (soluble calcium oxalate)

    Oxalis is a large genus of flowering perennials comprising of 800 species found throughout the world. Many oxalis species are considered weeds, however, some species are grown as houseplants. One of the most outstanding of the oxalis species is Oxalis triangularis, commonly known as purple oxalis.

    Plant defenses

    Thorns on a rose

    Plants have evolved many defense mechanisms to protect themselves from herbivory, such as thorns, trichomes (leaf hairs), chemicals, and razor-sharp crystals. Oxalic acid is a common compound in plants and occurs in two forms; soluble and insoluble.

    • Insoluble oxalic acid is the most common type which forms clumps of needle-sharp crystals called raphides in the tissues. When an insect or animal chews these types of plants, raphides are released which cause intense pain to the oropharynx. Due to pain and discomfort, domestic pets will usually stop chewing plants containing insoluble calcium oxalates. Common houseplants which contain insoluble oxalates include Dieffenbachia (dumbcane), Zantedeschia (calla lily), Syngonium podophyllum (arrowhead plant),  Spathillium (peace lily), Philodendron, Epipremnum aureum (pothos), Schefflera (umbrella tree), Colocasia (elephant’s ear) and Aglaonema (Chinese evergreen).
    • Soluble oxalic acid-containing plants are considered more harmful because of the potential to cause hypocalcemia and acute kidney damage. Plants include spinach (which also contains insoluble calcium oxalate crystals) and rhubarb.

    The degree of toxicity depends on the duration of exposure and the amount of plant consumed. Livestock are at greatest risk as they are more likely to consume large quantities of the plant. The bitter taste of oxalic acid is generally enough to deter most cats and dogs from eating enough to cause sickness.

    Related: Plants toxic to cats

    Is oxalis toxic to cats?

    Shamrock plant (Oxalis spp) is toxic to cats. The toxic principle is oxalic acid which is rapidly absorbed in the gastrointestinal tract and binds to systemic calcium causing blood calcium levels to drop suddenly (acute hypocalcemia) and calcium oxalate (CaOx) deposition in the renal tubules, leading to acute renal (kidney) failure. Cats can experience gastrointestinal symptoms including vomiting, diarrhea, drooling, and poor appetite. Tremors have also been reported, likely secondary to hypocalcemia.

    Toxicity class – how dangerous is it for my cat?

    The oxalis plant is moderate to severely toxic to cats and can cause death secondary to acute renal failure.

    What happens if a cat eats a shamrock plant?

    Clinical signs of oxalis plant ingestion include:

    • Weakness
    • Lethargy
    • Hypersalivation (drooling)
    • Gastrointestinal signs (loss of appetite, vomiting, diarrhea)
    • Tremors secondary to hypocalcemia
    • Kidney damage 24-36 hours after ingestion (altered urine output, blood in the urine, increased thirst)

    How much would a cat need to eat to experience serious issues?

    There is no toxic dose, and symptoms will depend on the amount of oxalis ingested as well as the overall health of the cat. Cats who are dehydrated or have chronic kidney disease are at increased risk. Due to the bitter nature of the plant, large amounts of the plant are not often ingested.

    What should you do if your cat has ingested oxalis?

    In most cases, cats will ingest an insignificant amount of oxalis to cause clinical signs. If a large amount has been ingested, seek immediate veterinary care.

    As always, if you are unsure of the toxicity of a plant, contact your local veterinarian or animal poison control for further advice.

    Do I need a first-aid kit at home?

    While first aid kits are amazing resources that all pet owners should have on hand, they are unlikely to be beneficial in the event of Oxalis toxicity, and prompt veterinary intervention is recommended.

    Signs you need to see the vet / How can the vet help?

    You should seek veterinary advice if your cat has ingested any amount of the plant. Concerning signs include vomiting more than 3 times, anorexia, weakness, tremors, ongoing diarrhea, or decreased urine output. Your veterinarian will perform an exam and discuss diagnostics if necessary.

    If significant clinical signs have developed, treatment may include fluids to treat or prevent dehydration and a bland diet to rest the gastrointestinal tract. Tremors will be treated with intravenous calcium supplementation. Cats with acute kidney injuries generally need to be hospitalized for several days until the kidney injury has improved.

    Could my cat die if they eat an oxalis plant?

    Yes, cats can develop life-threatening acute kidney injury or hypocalcemia leading to neurological or cardiac disturbances that can lead to death.


    Prognosis is dependent on the amount of plant ingested, the severity of clinical signs, and the response to treatment. Cats with moderate to severe toxicity may have a guarded prognosis.

    Should I keep oxalis plants if they are poisonous? How to keep them safely?

    Given the toxicity associated with these plants, keeping them within reach of cats is not recommended. If you do wish to have them within your home, keep them in a room away from cats or stored within a growing cabinet that your cat cannot access. They can also be grown outdoors. 

    Is shamrock poisonous to humans?

    • Yes, the plant is toxic to cats, dogs, and humans.

    Frequently asked questions

    What parts of the oxalis are poisonous or toxic?

    • All parts of Oxalis are toxic due to it containing oxalic acid.

    What does a shamrock plant taste like?

    • Oxalis plants are bitter/sour and generally are not palatable.

    Can I eat raw oxalis?

    • No, oxalis is toxic to humans and has a very bitter/sour taste that is not enjoyable.

    What’s the difference between a shamrock and a clover?

    • Clovers are small green plants that have three leaves. The shamrock plant has three triangular-shaped leaves in a variety of colors including green and purple.

    Feature image Kevin, Flickr


    • Julia Wilson, 'Cat World' Founder

      Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio

    • Dr Paula Simons, Veterinarian

      Dr Paula Simons graduated from the Ontario Veterinary College with a Doctorate in Veterinary Medicine (DVM) in 2019. She is currently working at 'Cornell University Veterinary Specialists' (CUVS) in Connecticut as an Emergency and Critical Care veterinarian resident (see her work profile). CUVS is a 24/7 Emergency and Critical Care Facility certified by the Veterinary Emergency & Critical Care Society, indicating the highest level of patient care.