Lilies have an unknown toxin in lilies leads to kidney failure that can be lethal. Just two leaves from a lily plant can cause poisoning in cats, and even the pollen from a lily plant can have these toxic effects on cats. Cats are commonly exposed to lily pollen from grooming the pollen off their coats. Due to cats' extreme sensitivity to lilies, it is recommended to keep lilies out of and away from cat households.  Some examples of lilies include Easter lily, tiger lily, Japanese show lily, Rubrum lily, and day lily. Some "lilies" are not "true lilies" or "daylilies" and will not cause kidney failure; however, many have other properties that cause other types of toxicity. For more information on lilies and their toxicity to cats, please read some more information from the FDA.