Tinsel, chocolate, and holly are all festive signs of the holidays -- but all can hurt your pets.

Veterinarians see many sick pets this time of year because owners often don't know what foods, plants and decorations are dangerous for their animals.

Dr. Lisa Olsen is an emergency veterinarian at Iowa Veterinarian Specialties and she says this time of year can be very busy.

"We see a lot of problems related to food in an emergency clinic during the holidays,” she says. “Sugar-free sweeteners can be a big hazard that we don't think of for our pets."

There are other recipes for disaster in kitchens during the holidays. Grapes and raisins found in holiday breads and cakes, macadamia nuts, and, of course, chocolate are all very dangerous for cats and dogs.

In many cases, animals that eat dangerous foods will need a few nights stay at a pet hospital. Vets also warn owners that while the season is about giving, they should refrain from giving leftovers and scraps to pets.The high fat foods can be bad for pet's digestive systems and cause weight gain.

Holiday decorations pose another danger to pets.

Dr. Bill Williams, a veterinarian at Hubbell Animal Hospital in Des Moines, Iowa, says that owners should be very aware of what their pets are getting into.

"Toddler proofing the house is the way we look at it,” Williams says. “Because dogs are in many cases, perpetual toddlers they're always into something."

Animals can get extremely sick if they eat tinsel or string. And owners should make sure their pets don't play with glass ornaments. The ornaments can be knocked off Christmas trees and cause cuts to the mouth or paws.

Overly curious cats and dogs can hurt themselves badly if they topple the Christmas tree. The needles can be poisonous and cause irritation if eaten. There are other traditional holiday plants that also can be dangerous.

"Mistletoe is very dangerous. It can cause breathing problems, seizures, and even death," says Olsen.

Poinsettias, lilies, and holly are also toxic. Just a few lily petals can cause severe kidney failure in cats.

If you suspect your pet has eaten something dangerous call your vet so the problem can be resolved before it requires expensive surgery.

"The most common signs of any kind of intestinal object is going to be vomiting, diarrhea, loss of appetite, lethargy, or any kind of abdominal pain," says Williams.

If you're not sure if the plant or food you pet has eaten could be toxic, check the ASPCA poison control site for a list.

And if you plan to dress you pet as Santa Claws, make sure the outfit is loose fitting and does not restrict movement; and never leave pets unattended if they are in festive wear.

Vets also recommend pets should not be given as gifts during the holidays. While it can be cute to see a puppy pop out of a wrapped box, they are a long-term responsibility.

"If you're not the one going to be taking care of it, don't give them as gifts is the best rule of thumb," says Williams, adding that a busy household is a bad place to introduce and begin to train a new animal.