Yes, cats are highly allergic and toxic to lilies. True lilies (Lilium species) and daylilies (Hemerocallis species) are extremely poisonous to cats and can cause severe, potentially fatal kidney failure. All parts of these lilies—including petals, leaves, pollen, and even the water in the vase—can cause toxicity. Even small amounts of ingestion or pollen exposure can lead to symptoms such as vomiting, lethargy, drooling, and rapid kidney damage that can be irreversible within about 18 hours. Because of the severity of the toxicity, it is strongly advised that households with cats do not have lilies inside the home or in the yard where cats can access them.

Some lilies with "lily" in their name, like peace lilies and calla lilies, do not cause kidney failure but can still cause milder irritation. However, the true lilies and daylilies are the most dangerous and should be strictly avoided around cats.

In summary, lilies are not just an allergy risk but a toxic plant that can cause fatal poisoning in cats, so they should be kept away from any environment where cats live or roam.