Poinsettia (Euphorbia pulcherrima)
Why we grow it: If you live in a warm, subtropical area like southern California, you might add the leggy poinsettia shrub to your yard. But most people bring the potted variety into their homes during the holiday season to deck out wreaths, dining room centerpieces, or fireplace mantles with its bright red leaves.
Deadly parts: The milky sap found in the veins of the plant.
Toxic toll: Despite its toxic reputation, poinsettias will never top the list of most poisonous plants, as there's only been two documented cases of them causing human death. But you'll want to teach kids not to touch or consume the plant, nonetheless. And as far as cats and dogs are concerned, keep poinsettia plants out of reach—unless you want to clean up after pet vomit and diarrhea. Take extra precautions if you have elderly, ill, or young pets.