A pack of sugar-free gum normally retails for $1.19, but Taunya Whipple's last pack cost about $700.

On Jan. 10, Whipple and her husband, Ian, headed outside to shovel snow. They left Lewis, their 2-year-old Polish lowland sheepdog, inside their Hilliard                      condominium, never suspecting he'd find a way into Mrs. Whipple's purse and the gum inside.

"He'd chewed on things before, but never something like this," said Mr. Whipple, a student at the Ohio State University College of Optometry.

The couple didn't panic at first. Mrs. Whipple recalled that her childhood pet, a Yorkshire terrier, had occasionally eaten gum.

Just to be safe, Mrs. Whipple called her

father, a veterinarian in Utah. While her husband searched the Internet for a list of the gum's ingredients, she asked whether they needed to take Lewis to a vet.

"At first he said Lewis would be fine," Mrs. Whipple said, "but then Ian told me to tell him that the gum was sugar-free and had xylitol in it. That's when he told us               we had to get him to emergency (treatment) right away."

Xylitol is a highly concentrated and purified form of xylose, a naturally occurring sugar alcohol. Though used since the 1960s as a sugar substitute in Europe,                                       its use in the United States has been on the rise only during the past decade. It's found in gum, chewable vitamins, baked goods and other foods.

And, as the Whipples learned, xylitol is toxic to dogs.

According to a study published in 2006 by the American Society for the Prevention of Cruelty to Animals, xylitol triggers an insulin response in dogs that can                                bring on hypoglycemia, liver failure and death.

The study estimated that 10 pieces of sugar-free gum can kill a 65-pound dog. Lewis, at about 35 pounds, had eaten nine, Mrs. Whipple said.

Dr. Sharon Gwaltney-Brant, medical director of the ASPCA's Animal Poison Control Center in Urbana, Ill., said only dogs so far have been known to have problems                             with xylitol.

Xylitol poisoning was among the 17,453 calls received for "people food" poisonings in 2009, which included cases involving grapes and chocolate, the ASPCA                            reported.

In its natural form in foods such as strawberries, plums, endive and mushrooms, the level of xylose is small and should not cause problems in dogs, Gwaltney-Brant                            said.

Lewis, however, had eaten gum. For 24 hours, he was subjected to an array of treatments, first at the Capital Veterinary Referral & Emergency Center in Columbus,                              then at the Whipples' veterinarian's office in Hilliard. Though his blood-sugar levels dropped significantly, Lewis pulled through and is now back to his perky self.                             The bills for his treatment totaled nearly $700.

Now, the Whipples are hoping to educate other dog owners about the dangers of xylitol poisoning.

They also have contacted the gum's manufacturer to consider placing a warning label on the gum's packaging. "We had no idea it was that bad," Mr. Whipple said.                "He's back to normal now, and we feel blessed, but if we can help avoid this happening to someone else, we'd like to try."

janeehawes@verizon.net