If Snopes and scientific studies aren’t enough, perhaps reports at the Wall Street Journal, CBS News, and Nature World News can sway you: A sugar substitute found in chewing gum and other everyday food and household items can make dogs sick and even kill them.

Veterinary experts say xylitol—also used in toothpaste, gummy vitamins, some peanut butters, and breath mints—is about 100 times as toxic as milk chocolate to dogs, and it’s being blamed for an uptick in accidental pup poisonings, say animal poison-control centers. The ASPCA’s poison center, for instance, received more than 3,700 xylitol-related calls last year, with nearly a dozen deaths. And a toxicologist from the Pet Poison Helpline says it’s seen a “dramatic increase” in calls related to the sweetener, with only 300 in 2009, but 2,800 so far this year.

The problem xylitol poses for dogs is it causes a sudden surge of insulin after they eat it, which makes blood pressure plummet, possibly resulting in seizures, brain damage, or liver failure. And it takes just a small amount: As little as 50 milligrams of the sweetener per pound of body weight can be toxic, so even one or two pieces of gum can make a small dog ill.