Poinsettias are widely believed to be poisonous to children and pets. That's only partly true; poinsettia leaves can cause discomfort and indigestion when consumed, but that's when eaten in large quantities. Mistletoe and holly are far more toxic and should be placed up high on a shelf or countertop where pets and children cannot reach them. To play it completely safe, opt for artificial versions of these seasonal mainstays instead of the real deal. If anyone accidentally consumes either mistletoe or holly, a call to poison control is in order.