There is a page with items about Lilies and choclit here - on Fab Cats
http://www.fabcats.org/owners/poisons/article.htmlI would be tempted to add that onions, leeks and garlic are all part of the lily family and therefore all poisonous to cats.
PRETTY DEADLY
A vase of lilies may look pretty standing on your table, but if you have a cat, beware!
The plants of the lilium species are among the most dangerous for cats. These include day lily (hemerocalis species), Easter lily, stargazer, rubrum, tiger and Asiatic lilies (all of the Lilium family). Symptoms of poisoning from these plants include protracted vomiting, anorexia and depression and ingestion can cause severe, possibly fatal, kidney damage.
If your cat shows signs of possible poisoning, seek veterinary help immediately. For more information on potentially poisonous plants for cats, click here