House plants like lilies, chrysanthemums, cyclamen, ferns, ivy, hyacinth and amaryllis are highly toxic to cats. Check your plants against a plant identifier and look up their toxicity to cats online, or ask someone knowledgeable to look around your garden. If your cat has eaten a plant and is behaving oddly, take it and the plant to the vet. Early treatment can save a pet but the longer it is left, the more damage can be caused to its organs, and recovery is less likely.