Why Are Lilies So Toxic To Cats?

What is lily poisoning?

There are lots of flowers and plants called lilies, but it’s species of true lilies – those belonging to the Lilium genus – and daylilies – the Hemerocallis genus – that cause what’s known as lily poisoning or lily toxicity. Other lilies outside of these groups might also be toxic, but not as harmful, or affect different parts of the body.

When any part of a lily is ingested, it affects a cat’s kidneys, causing them acute damage. This can lead to kidney failure in as little as 24 hours and if left untreated, it ends up becoming fatal.

It only takes a little nibble or sip for that to end up being the case, too. “[Lilies are] so poisonous that a cat can suffer fatal kidney failure just from biting into a lily leaf or petal, licking lily pollen from its paws, or drinking water from a vase with cut lilies in it,” said Dr Larry Cowgill, Professor Emeritus at the UC Davis School of Veterinary Medicine, in a statement.

A mysterious toxin

Given how certain it is that lilies are harmful to cats, and the seriousness of their toxicity, it’d be easy to assume that scientists also know exactly what it is about them that makes them so dangerous. 

However, these things are easier said than done. It turns out that the toxin behind lily poisoning is yet to be identified, although scientists have got some ideas. 

According to a 2010 paper, there’s a suggestion that the toxin is actually a metabolite, the product of a non-toxic compound within lilies being broken down within the cat once ingested. It’s also been proposed that such a metabolite is cat-specific, given that it doesn’t appear to have the same effects in other animals, like dogs (although eating lilies might give them an upset stomach).

While there are some treatments for lily poisoning – including stomach emptying, activated charcoal, and a fluid drip – the unfortunate consequence of not knowing the specifics of the toxin and its mechanism of action is that it has made it difficult to develop a more specific, targeted therapy for it.

What to do if your cat eats a lily

As you’ve likely gathered, lily poisoning is pretty awful, so stopping it from happening in the first place is key. The easiest way to do this is by not keeping lilies in the house, and if you have an outdoor cat, don’t plant any in the garden.

Of course, we don’t have eyes in the back of our heads, and it’s possible that our kitties might’ve had a chomp on a lily without us knowing. In that case, early symptoms to look out for can include vomiting, drooling, and eating less. Cats might also be less energetic or appear weaker than usual.

If any of those symptoms appear, the best thing to do is contact a vet immediately.