Holiday budget: $537 for presents, $52 for decorations ... and $300 to have the dog's stomach pumped?
This year, the average shopper will spend $737.95 on holiday expenses, reports the National Retail Federation. But pet owners budgeting for the holidays may also want to factor in the cost of an emergency vet visit for when their dog or cat eats something it shouldn't, an occurrence veterinarians say is more common this time of year.
"We always talk about Halloween as being the start of chocolate season," said Dr. Tina Wismer, medical director of the American Society for the Prevention of Cruelty to Animals' Animal Poison Control Center.
Pets have access to quantity this time of year from a trick-or-treater's bag or a present under the tree. But the treat, which is toxic to cats and dogs, can trigger vomiting, diarrhea and—if eaten in larger amounts—seizures and even death, she said.
(Read more: What happens to reward miles upon death?)
"If she ate 15 Hershey's kisses, that would be a really big dose." That's what Cole Wolfson of Pittsburgh recalls emergency vets saying when he and his wife arrived home two days before Christmas to find their 15-pound Chihuahua-Corgi mix Deeka had raided a wrapped box of chocolates left beneath the tree.
The discerning pup had spit out the centers of the cherry cordials and avoided the cocoa-dusted truffles, but had still consumed a dangerous amount for her small size. Deeka seemed fine—"She was just bouncing around like it was nobody's business. She had never had that much sugar in her life," said Wolfson—but vets pumped her stomach and administered an electrocardiogram as a precaution.
Chocolate isn't the only problem. Incidents of accidental poisoning from items including cold medicines, rodenticide and alcohol are elevated during the holiday season. Seasonal plants including poinsettias and mistletoe prompt emergency calls, as do scraps from the Thanksgiving table.
Last year, the APCC received about 28 calls per day in the two weeks around both Halloween and Christmas—a 20 percent increase compared with the rest of the year. Pet insurance provider Petplan reports bigger jumps. Policyholders are 91.6 percent more likely to file a claim related to food poisoning during the week between Christmas and New Year's than any other week, it said, and 235 percent more likely to report chocolate ingestion.
(Read more: Teaching kids charity? Skip the soup kitchen trip)
The average claim last year associated with such accidental poisoning: $465, plus a deductible of $50 to $200. If the pet ingested an inedible "foreign body," such as tinsel or candy wrappers, that figure nearly triples to $1,284.
"She was just bouncing around like it was nobody's business. She had never had that much sugar in her life."
"If my dog ate a whole bag of those fun-size bars, I'd be more worried about the wrappers than the chocolate," said Dr. Jules Benson, vice president of veterinary services for Petplan.
Dogs are the culprits in the majority of accidental poisoning cases. "Cats don't have the same sweet tooth," said Wismer.
Jennifer Fox started kenneling her dogs on Halloween night after her Labrador retriever, Kodie, ate candy from her kids' trick-or-treating stash two years ago. "You turn your back for a second, and he's got his head in it, eating it wrapper and all," she said. "I didn't know how much he'd gotten into, but it turned out, it was all of it."
Kodie vomited up most of the candy and wrappers on his own, on the way to the vet's office. There, vets gave him fluids for dehydration. The incident cost nearly $620, all but $100 of which was covered by pet insurance, Fox said.
(Read more: Here's how to stretch your holiday spending budget)(
Scraps from the Thanksgiving table and holiday parties are another danger. Not only are there likely to be toxic-to-pets ingredients such as garlic and onions in dishes, but trash-fishing pets may contract food poisoning.
"Grandma's potato salad ends up in the garbage, and the dog can knock over the garbage can," said Dr. Kevin Fitzgerald, a veterinary specialist with the VCA Alameda East Veterinary Hospital in Denver. "It's a petri dish for bacteria."
Or worse. "Scraps can be a danger of 6, 7, 8 on a scale of 10, versus 2, 3, 4 for chocolate," said Benson. Fatty scraps can lead to pancreatitis. Turkey bones, if ingested, can splinter or become lodged in the digestive tract.
Then there are more unusual holiday risks. "We always worry with cats at Christmastime, about that tinsel you put on the tree," Benson said. If ingested, he said, "it anchors in the near part of the gut," and can cut through the digestive tract. Ribbon and ornaments pose problems, too.
In 2011, Chatham, N.J., resident Ashley Tate found her poodle, Normandy, chewing on the metal topper for a Christmas ornament. A desperate search failed to turn up the glass ball that had been attached to it.
"I feel like I dodged a major bullet."
"I immediately drove to the vet," Tate said. "I didn't call them or anything. I just showed up at their door." X-rays confirmed her fear: Normandy had eaten the ornament. "You could see the pieces of glass in her stomach," she said.
Tate had acted quickly enough that vets were able to treat Normandy by helping the glass pass through her system, rather than resort to surgery. "Luckily I only had the $100 emergency vet bill," she said. "I feel like I dodged a major bullet."
Pet owners' best course of action is to be vigilant about pet-proofing. Be aware of seasonal items that can be toxic or otherwise dangerous, and secure them out of pets' reach, Fitzgerald said. Assume pets can sniff out edibles through gift wrapping or a plastic trick-or-treat bucket.
It's also important to warn houseguests and other holiday visitors. "You and I may know we can't leave our purse or backpack with food or medications in it on the floor," said Wismer. "But a visitor may not."
—By CNBC's Kelli B. Grant. Follow her on Twitter @kelligrant.