What is the toxic compound in lilies that poisons cats?

Conclusion: We don't know.

I've been searching high and low for an answer to the question in the title. I've visited numerous studies on the Internet and websites. I've come up with a blank because in a study called Specific Syndromes Causing Acute Intrinsic Renal Failure, the author Dennis J. Chew DVM and colleagues, states: "Ingestion of lilies is highly toxic to cats. The specific toxic principle is unknown but all parts of the lily are toxic to cats".

RELATED: The top 10 cat poisons in the USA and lilies are in the number 1 spot.

Lily Pollen Kills Cats. Photo by wlcutler

And in another study call Blood Purification for Intoxications and Drug Overdose concerning lily ingestion the scientists state that "The main toxin responsible for acute tubular necrosis in cats is still unknown".

Lilies cause acute kidney injury in cats.

It is worth noting perhaps that lily of the valley does not contain a nephrotoxin (a toxin which damages kidneys) but does contain a digitalis-like toxin: cardiac glycosides.

Finally, another study dated 2004 by Konnie H Plumlee DVM states in respect of the poisoning of cats by lilies: "Because the toxins of these lily species has not been identified, true toxicokinetic data is not available".

The answer to the question in the title is that we don't know the answer! Unless somebody can come forward and leave a valuably informative comment which I would be greatly indebted! 

Please remember though that every part of the lily is toxic to cats even the pollen. However, the picture is very complicated because there are some lilies which are not toxic to cats. And there are many species of lily as I recall including hybrids.

RELATED: Which lilies are not poisonous to cats?

The overriding message must be to be abundantly cautious and not to have any lilies of any species in the home if you are the caregiver of a domestic cat or cats. They are just too dangerous.