As beautiful as poinsettas are, some cats find them irristable. Though they are not extremely "poisonous", as most people think, they can cause drooling and sometimes mild vomiting and diarrhea. Mistletoe and holly are actually more toxic. If eaten in large amounts, severe vomiting, diarrhea, difficulty breathing, heart problems, strange behavior and loss of appetite can result. My own cats love to chew on any plant they can, so I keep all plants in a room they are not allowed in or store them out of reach. If you know your pet has ingested any of these plants and is showing symptoms medical help will be needed.