Oh, Christmas trees. The traditional holiday item can brighten a home with sparkling lights, dazzling ornaments and a plethora of presents below. But Christmas trees can be potentially dangerous for pets, such as dogs and cats.

With the holiday season in full swing, read on for a look at how Christmas trees and other seasonal items may prove to be a problem for your pet.

Christmas trees

Make sure your pets are safe this holiday season. (iStock)

Needles and tree water are two of the most dangerous aspects of the holiday item for your cat or dog. According to PetMD, the trees’ needles can cause “gastrointestinal irritation” if ingested by a cat or dog, as well as possibly causing an obstruction or puncturing the animal’s intestinal lining.

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“The oils produced by fir trees can be irritating to a pet's mouth and stomach, causing excessive vomiting or drooling,” the site notes.

Pet supply company Hartz also warns on its website that the needles are considered to be “mildly toxic,” while Modern Dog Magazine also says the pine needles can damage a pet’s eyes if they were to run into the tree, potentially resulting in a corneal laceration.

Tree water, too, can prove to be hazardous. In fact, the water can poison pets after “only a few laps,” PetMD states. Different substances used to keep the tree fresh and healthy — such as a preservative, fertilizers, pesticides and even aspirin — can harm your furry friend.

"Even untreated water may cause problems, so don’t allow your dog access to the tree water. It’s best to cover the tree stand and water to prevent a dog from getting to it," Jerry Klein, the chief veterinary officer at the American Kennel Club (AKC), told Fox News..

But the danger isn’t limited to live trees. Fake trees can be an issue for your dog or cat as well.

“Be extra vigilant if you use an artificial tree, especially as it becomes more brittle with age. Small pieces of plastic or aluminum can break off and cause an intestinal blockage or mouth irritation if ingested by your dog,” Hartz warns online.

Other hazardous holiday items

Poinsettia

For cats, specifically, the U.S. Food and Drug Administration (FDA) warns these festive red and white plants can be harmful to your fluffy feline.

In fact, poinsettias “have a milky white, latex sap that can be very irritating to his mouth and stomach,” the FDA states online. That said, poinsettia toxicity is relatively mild — typically resulting in drooling, vomiting and diarrhea, which usually betters after a couple of hours.

Mistletoe

While hanging mistletoe may be a romantic gesture this holiday season, certain substances found in the plant could harm your pet.

Lectins and phoratoxins — two chemicals found in mistletoes — can “affect the heart, causing low blood pressure and slowed heart rate,” the FDA says.

Thankfully, “severe mistletoe toxicity is uncommon and usually only occurs if your pet eats a large amount,” the agency continues. Cats and dogs who eat mistletoe may have diarrhea or vomit.

And for those who hang mistletoe in a barn, the plant can cause colic (a sometimes serious belly ache) if eaten by horses, the FDA warns.

“If you see these symptoms in your pet and suspect or know they ingested mistletoe, you should seek veterinary assistance as soon as possible,” Dorothy Black, clinical assistant professor at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences, told the Modern Dog Magazine. “Mistletoe shouldn’t be used where pets could possibly reach it.”

Lights, tinsel and ornaments

Lights can become too hot and potentially burn animals that come into contact with them, warns Hartz. Dogs or cats that chew on the wire could also unknowingly put themselves at risk to suffer an electric shock or mouth burn.

"Chewing on an electric wire also can cause pulmonary edema (fluid in the lungs) which can be fatal," Klein said.

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Tinsel, if ingested, can block intestines “causing decreased appetite, vomiting, diarrhea, lethargy and weight loss,” Hartz also warns.

"Surgery is often necessary to remove the tinsel. This is especially true for cats," Klein added.

Edible or glass ornaments can be a danger to pets as well, especially if a dog or cat knocks the tree over and steps on or eats pieces of the broken ornament.

“Swallowing an ornament also can cause a gastrointestinal blockage. Some ornaments may be lethal depending upon the materials or chemicals used to create them,” Hartz states.