Is Shamrock (Oxalis) Plant Toxic to Dogs?

Is shamrock plant toxic to dogs?

Shamrock plant (Oxalis spp.) is toxic to dogs. The toxic principle is oxalic acid which binds to systemic calcium leading to a dangerous drop in blood calcium levels and deposition of calcium oxalate (CaOx) in the delicate renal (kidney) tubules, leading to acute kidney failure.

Calcium is the most abundant mineral in the body, 99% of calcium is stored in the bone, and the remaining 1% is located in the extracellular fluid. Several essential functions rely on calcium including conduction of electricity in the body, cardiac function, nerve impulses, blood clotting and muscle contractions.

The risk to dogs is minimal as the bitter-tasting leaves will deter most dogs. Hypocalcemia and acute kidney failure typically occur when a large volume of oxalis has been consumed, which is more common in livestock than in dogs or cats.

Shamrock poisoning can be acute or chronic. Acute cases occur when the dog consumes a large amount of plant matter over a short period which causes calcium levels to drop to dangerously low levels. Chronic shamrock toxicosis occurs when the dog consumes smaller amounts over an extended period leading to a build-up of calcium oxalate crystals in the kidney tubules.

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, Purple shamrock,
  • Life cycle: Perennial
  • Sun exposure: Full, partial
  • Toxicity: Toxic to dogs
  • Soil type: Loamy, sandy, well-drained
  • Toxic parts: All parts
  • Severity: Moderate
  • Toxic properties: Oxalic acid (soluble calcium oxalate)

Also known as wood sorrel, oxalis is a genus of 800 herbaceous flowering plants native to Southern Africa and tropical Southern America. Two species are of particular note because of their popularity as a houseplant. The most well-known oxalis plants are:

Oxalis triangularis (purple oxalis): Three showy, deep purple, triangular-shaped leaves

Purple oxalis
© Julia Wilson

Oxalis tetraphylla (iron cross oxalis): Four rich green heart-shaped leaves with a dark purple centre

Iron cross oxalis
Photo by StephenVanHove/Shutterstock

Clinical signs

Symptoms of oxalis toxicity will depend on the amount ingested and any underlying medical conditions the dog may have. Dogs with chronic kidney disease are at the greatest risk.

  • Drooling (due to the bitter taste of oxalis)
  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Tremors
  • Weakness
  • Changes in thirst and urination
  • Bloody urine


Most dogs won’t ingest enough shamrock plant to cause clinical signs. However, if a large amount has been ingested over a short period or if the dog has been routinely consuming shamrock plant, or if symptoms develop, seek immediate veterinary attention.