Mistake: You let the dog drink water from the tree stand.
That tree stand is probably filled with water that’s far from fresh. Tree preservative, often made with fertilizer and fungicides, can cause vomiting or upset stomach in pets; bacteria can also multiply in the standing water. Snugly wrap a tree skirt around the trunk to make the water harder for your pet to get to.
Mistake: You hang a few “indoor” lights outdoors.
Many holiday lights manufactured today are intended for both indoor and outdoor use, but you may come across some that are location specific. Indoor lights aren’t as resistant to moisture, which may cause electrical shorts and damage in wet weather. Many products tested for safety in the United States are labeled with a UL tag (for Underwriters’ Laboratories, a certification company that inspects such products). Indoor lights have a tag marked with a green UL. Outdoor lights are marked with a red UL.
Mistake: You keep poinsettias in reach of your kids and pets.
This one is actually not as risky as you might think. Despite its “poisonous” reputation, the plant is only mildly toxic. A 50-pound child would need to eat more than 500 poinsettia leaves to reach potentially toxic levels, and no deaths have been documented from consumption. A child may get queasy or throw up after eating, say, five poinsettia leaves—but not much more will happen. (Plus, the leaves taste unpleasant, so it’s unlikely many would be consumed.) The plants may cause drooling, vomiting, or diarrhea in cats and dogs, but medical treatment is rarely necessary unless symptoms are severe. To be safe, keep poinsettias out of the reach of pets and young children, but there’s no need to banish your favorite holiday plant.
Sources: nfpa.org, christmastreeassociation.org, realsimple.com, doityourself.com, webmd.com, petpoisonhelpline.com, medicinenet.com, lifehacker.com, chicagotribune.com, energy.gov