I am a "dog" person so this tip fall under the category of "who knew" but lilies of many varieties are poisonous to cats. According to the ASPCA lilies are considered to be highly toxic to cats. While the poisonous component has not yet been identified, it is clear that with even by ingesting very small amounts of the plant, severe kidney damage could result. The Society of American Florists recommends keeping lilies out of the reach of cats. It is important to note that lilies do not pose a problem for other pets or humans.