If you have a cat, never let lilies in the house

This is the one plant worth being absolute about, because there's no safe dose and there's a real clock on it. True lilies (Lilium, so Easter, tiger, Asiatic, Oriental, stargazer) and daylilies (Hemerocallis) cause acute kidney failure in cats. Every part of the plant is toxic. Petals, leaves, stem, the pollen, and the water in the vase. A cat that brushes past a bouquet and then grooms pollen off its own fur has been exposed. Chewing one leaf can be enough. The FDA and the vet schools all land on the same timing: treatment started within roughly 12 to 18 hours of exposure is what saves cats. Past that the kidneys are often already gone. Early signs are vague and start within a few hours, so drooling, vomiting, going off food, hiding, generally acting flat. Then they can look like they've recovered, which is the trap, because that's exactly the window where the kidney damage is happening quietly. If you think there's been any exposure at all, don't wait for symptoms. Go, and bring the plant or a photo of it so it can be identified properly. Not every plant with lily in the name is one of these, for what it's worth. Peace lily, calla lily and lily of the valley are different plants with different problems, still not cat food but not the kidney failure ones. Peruvian lily isn't a true lily either. If you can't tell which you're looking at, treat it as the dangerous kind. Practical version: tell people not to send you flowers with lilies in them. Most florists will substitute without blinking if you ask. It's a small thing to ask for and it's probably the highest value item on the whole cat proofing list.