Lilies & Cats: Danger is Blooming

Lily Toxicity in Cats

Did you know lily exposure is the number one reason cat owners contact pet poison control? Lilies were responsible for about 6% of total calls by cat owners to the ASPCA pet poison control center (8). Popular in home gardens and flower arrangements, lilies are unfortunately very toxic to our feline friends and can cause kidney failure and death. The entire plant is poisonous to cats, with the flower portion believed to be more harmful than the leafy portion. The exact toxin remains unknown, other than that it is a water-soluble compound found in all parts of the plant (5). The toxic dose is also unknown, but ingestion of even a tiny amount of the lily plant is dangerous- as little as a part of a single flower can cause death (2). Fortunately, with prompt treatment, most cats who ingest lilies will have a positive outcome.

Different Kinds of Lilies

One confusing aspect of lily toxicity is that there are many plants we refer to as “lilies.” Only lilies of the genus Lilium (“True Lilies”) and  Hemerocallis (Day Lilies) are known to cause kidney failure in cats. Common types of True Lilies include Easter Lily, Asiatic Lily, Tiger Lily, Wood Lily, Stargazer Lily, and Rubrum Lily (9). Daylilies are commonly planted in home gardens, while true lilies are often found in flower arrangements. Interestingly, other species, including dogs, cats, and humans, do not suffer from renal toxicity after lily ingestion.

What about the other “Lilies”? Calla Lilies (genus Zantedeschia), Peace Lilies (Spathiphyllum), Lily of the Valley (Convallaria), and Peruvian Lilies (Alstroemeria) are not associated with kidney toxicity. However, Calla and Peace Lilies contain insoluble oxalates, which can cause oral irritation. Cats may exhibit excessive salivation, pawing at the mouth, and anorexia. Veterinary treatment is often unnecessary for ingestion of these species and mainly consists of cleaning out the mouth and treating discomfort. Lilies of the Valley contain cardiac glycosides, and ingestion can cause heart problems such as arrhythmias. Veterinary treatment should be sought if a cat ingests Lily of the Valley, as hospitalization and anti-arrhythmic drugs may be needed. Alstroemeria flowers, on the other hand, are completely non-toxic! (9,6).

Symptoms & Diagnosis

Ingestion of true lilies and daylilies is associated with kidney disease and pancreatitis (as well as seizures in rare cases). Common clinical signs of lily toxicity include vomiting, depression, anorexia, polyuria (increased drinking), and polydipsia (increased drinking). At a cellular level, the toxin causes damage to the renal tubules and sometimes the pancreatic acinar cells. Typical findings on labwork include azotemia, hyposthenuria, proteinuria, and glucosuria (5). This can mimic many other causes of acute kidney injury in cats, including antifreeze poisoning and kidney infection, so getting a good clinical history is essential. Clinical history and diagnostic workup with bloodwork and urinalysis should help rule out some of these other causes of disease.

Treatment

Treatment consists of two main facets. The first is decontamination. Many cats will vomit on their own after lily ingestion, but attempting to induce vomiting is recommended if a cat is known to have eaten or chewed on a lily and has not vomited. Emetics such as xylazine or dexmedetomidine may be used. If a cat will not vomit and there is a strong suspicion that the lily is still in the stomach, gastric lavage can be considered. Administration of activated charcoal is also recommended. However, since the exact toxic compound is unknown, whether charcoal binds to the toxin is also unknown. Whether or not charcoal makes a difference in outcomes has yet to be established, so be sure to weigh the risks of giving charcoal (such as possible aspiration) against the benefits (2,4,7,8).

The second focus of treatment is fluid diuresis. This is thought to help clear the toxins more rapidly and keep the kidneys well-perfused. Ideally, cats with lily exposure should get 48 hours of IV fluid therapy with crystalloid fluids. Fluid rates vary based on clinician preference and the clinical presentation of the individual cat. Urine output should be monitored. Suppose a cat has anuric renal failure (no longer producing urine). In that case, dialysis is the only treatment that may avoid the death of the cat (6). A renal biopsy may be done before starting dialysis to see if the basement membrane of the glomerulus is intact and undamaged. If so, the kidney may be able to heal and regenerate with dialysis treatment. Unfortunately, dialysis treatment is not widely available, and the cost is often prohibitive. If a cat is oliguric (producing too little urine for the amount of fluid intake), furosemide is sometimes given to promote urine production to avoid dialysis (3,2,1,6).

Cats should also be monitored for signs of pancreatitis. Gastritis may also occur secondary to azotemia. Gastrointestinal support should be provided as needed, including anti-nausea medication and antacids (3,5,6).

Kidney values, electrolytes, and urine-specific gravity should be monitored every 24 hours for at least three days after lily ingestion. Some cats may have no change in their kidney values; some may have a temporary increase that goes back to normal with continued treatment, and some may, unfortunately, end up with lasting changes in the kidney values suggestive of permanent kidney damage (3,1,6).

Fortunately, most cats respond exceptionally well to treatment. A study conducted at the University of Pennsylvania Veterinary Hospital found that 100% of cats in a retrospective study survived to discharge from the hospital. 26% of those cats had signs of acute kidney injury (either azotemia on bloodwork or decreased urine specific gravity) during their treatment period, but only 9% of cats continued to have labwork abnormalities at the time of discharge. Interestingly, in that study, they did not find a difference in outcomes between cats who were treated soon after ingestion (less than 6 hours) and later (even up to 48 hours) (1). Another study published in JAAHA found that of cats who received veterinary care for lily ingestion, 87% had no signs of disease or brief clinical signs that resolved, 5% had longer-term renal disease, and 5% were euthanized due to renal failure (7). Some sources suggest that starting treatment within 18 hours of lily ingestion has a better outcome, but studies are few (3).

Takeaways

If a feline patient presents with known or suspected lily ingestion, here are the takeaway points:

1. Proper plant identification is critical. If you are unsure of the plant species, consider using a reverse image search to help you.
2. True Lilies (Lilium) and Daylilies (Hemerocallis) can cause life-threatening kidney disease in cats but are not toxic to dogs. Pancreatitis may also occur.
3. Treatment consists of decontamination, fluid diuresis, and GI support. Dialysis may be needed in severe cases.
4. Anuric renal failure is a grave prognostic indicator.
5. Most cats have a good outcome with prompt and proper treatment!

Check flower arrangements closely before bringing them into your house to avoid accidental exposure.

Avoid daylilies in your outdoor garden, as even if your cat stays inside, they pose a risk to community cats. If you are treating a cat for lily toxicity or are concerned your cat has eaten lilies, pet poison control can help. 

The two major pet poison control centers are:

• ASPCA Animal Poison Control Center: (888) 426-4435
• Pet Poison Helpline: (855) 764-7661

*There is a charge associated with both of these services.

If you are unsure if a plant a pet has ingested is poisonous, the ASPCA maintains a searchable list of plants that you can use to look up specific plants.

References

1. Bennett, A. J., & Reineke, E. L. (2013). Outcome following gastrointestinal tract decontamination and intravenous fluid diuresis in cats with known lily ingestion: 25 cases (2001–2010). Journal of the American Veterinary Medical Association, 242(8), 1110-1116. https://doi.org/10.2460/javma.242.8.1110
2. Fitzgerald, K. T. (2010). Lily toxicity in the cat. Topics in Companion Animal Medicine, 25(4), 213-217. https://doi.org/10.1053/j.tcam.2010.09.006
3. How to spot which lilies are dangerous to cats & plan treatment. (2024, February 15). ASPCApro. https://www.aspcapro.org/resource/how-spot-which-lilies-are-dangerous-cats-plan-treatment
4. Langston, C. E. (2002). Acute renal failure caused by lily ingestion in six cats. Journal of the American Veterinary Medical Association, 220(1), 49-52. https://doi.org/10.2460/javma.2002.220.49
5. Rumbeiha, W. K., Francis, J. A., Fitzgerald, S. D., Nair, M. G., Holan, K., Bugyei, K. A., & Simmons, H. (2004). A comprehensive study of easter lily poisoning in cats. Journal of Veterinary Diagnostic Investigation, 16(6), 527-541. https://doi.org/10.1177/104063870401600607
6. Schmid, R. D. (2023, November 1). Houseplants and ornamentals toxic to animals – Toxicology – Merck veterinary manual. Merck Veterinary Manual. https://www.merckvetmanual.com/toxicology/poisonous-plants/houseplants-and-ornamentals-toxic-to-animals
7. Slater, M. R., & Gwaltney-Brant, S. (2011). Exposure circumstances and outcomes of 48 households with 57 cats exposed to toxic lily species. Journal of the American Animal Hospital Association, 47(6), 386-390. https://doi.org/10.5326/jaaha-ms-5629
8. Swirski, A. L., Pearl, D. L., Berke, O., & O’Sullivan, T. L. (2020). Companion animal exposures to potentially poisonous substances reported to a national poison control center in the United States in 2005 through 2014. Journal of the American Veterinary Medical Association, 257(5), 517-530. https://doi.org/10.2460/javma.257.5.517
9. Toxic and non-toxic plants. (n.d.). ASPCA. https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants