Why lilies are dangerous
True lilies, in the Lilium and Hemerocallis groups, include Easter lilies, Stargazers, Asiatic lilies, tiger lilies and daylilies. According to the ASPCA, all parts of these plants are toxic to cats, including the pollen and the water in the vase. A cat that brushes against the pollen and grooms itself can get sick.
Other plants called lilies, like peace lilies and calla lilies, are not true lilies but can still irritate a pet's mouth and stomach. Lily of the valley is a different concern and can affect the heart. The ASPCA plant list (opens in a new tab) is the best place to check a specific plant.
If you think a cat has been exposed to a lily, contact a veterinarian right away. When sending flowers, tell the florist if there are cats in the home and ask for a pet-safe arrangement. Roses, sunflowers and many orchids are common safer choices.