The common Easter lily, the tiger lily, Asiatic or Japanese lily, and the numerous Lilium hybrids, and day lilies (Hemerocallis spp.) are highly toxic to cats causing nephrotoxicity that can prove to be fatal. The toxin responsible for the nephrotoxicity of lilies has not been identified. All parts of the plants are poisonous to cats, but especially the flowers. Deaths have been reported in cats after ingestion of only two leaves. Dogs, rats and rabbits were not affected after they were fed high doses of Easter lily experimentally.
Nephrotoxicity is known to occur in Britain, Norway and Japan following the ingestion of the lily known as bog asphodel (Narthecium ossifragum and N. asiaticum). Consumption of the flowers in particular causes renal tubular necrosis in cattle, suggesting that Lilium species also contain similar toxins.
The genus Lilium has approximately 100 species that are indigenous to Europe and Asia and North America. All species grow from bulbs consisting of overlapping fleshy scales that do not encircle the bulb as in the onion-type bulb. Leaves are arranged in spirals or whorls on the erect stems, and vary from grass-like, linear to lanceolate. The inflorescences consist of solitary flowers, racemes or umbels, with flowers being held erect, horizontal or pendent, and are generally large, showy and cup or funnel-shaped. Flower colors include white, yellow, orange, red, or maroon with frequent spotting on the inner surfaces of the petals. (Figures 1, 2) Numerous hybrids have been developed and are widely available commercially. The most common is the Easter lily (Lilium longiflorum)
Vomiting and excessive salivation
Cats suspected of eating lilies should be seen by a veterinarian as soon as possible after the plant was consumed. Gastrointestinal decontamination and fluid therapy is essential for preventing the nephrotoxicity. Vomiting, should be induced if the plant has been consumed within the last 1-2 hours. Activated charcoal with a cathartic should be given to decontaminate the gastrointestinal tract. Fluid therapy should be initiated to maintain renal function and prevent anuria. Fluid therapy should be continued for at least 24 hours. Once the cat has developed anuric renal failure, peritoneal dialysis or hemodialysis will be necessary to try and save the animal.
Within 3 hours of consuming 1-2 leaves or flower petals of the lily, cats start to vomit and salivate excessively. The cats become depressed, anorexic, with the initial vomiting and salivation tending to subside after 4-6 hours. Approximately 24 hours later, proteinuria, urinary casts, isosthenuria, polyuria and dehydration develop. Vomiting may recur at this stage. A disproportionate increase in serum creatinine as compared to blood urea nitrogen is a significant indicator of lily poisoning. As the cat develops, renal failure, anuria, progressive weakness, recumbency and death occur.
There has been no specific nephrotoxin identified in lilies to date, and so a presumptive diagnosis is made based upon the finding of the cat eating lily leaves or flowers, and the development of acute renal failure.
All members of the lily family, and especially the Eastyer lily should be considered highly toxic to cats.