Their report in the Journal of the American Veterinary Medical Association appears to strengthen the suspected link between the sugar substitute xylitol, thought to make dogs sick, and possible liver failure.
Xylitol, a naturally occurring product, is found in many sugar-free chewing gums, candies, baked goods and toothpastes.
Researchers Sharon Gwaltney-Brant and Eric Dunayer with staff at a poison unit of the American Society for the Prevention of Cruelty to Animals in Urbana, Illinois, gathered information on eight dogs treated between 2003 and 2005 after eating products containing xylitol.
Each dog became ill, and five died or had to be put down because of liver failure, possibly from ingesting xylitol.
One dog who had to be euthanized had eaten four large, chocolate-frosted muffins containing about 1 pound (0.45 kg) of xylitol.
"People don't think sugar-free gum can kill their dog. I didn't before I got into this. But this is something people should be aware of," Gwaltney-Brant, who co-authored the study with Dunayer, said in a statement.
Gwaltney-Brant said for dogs, ingesting even a small amount of xylitol can trigger significant insulin release, which drops their blood sugar and can be fatal.
"A 22-pound (10-kg) dog who consumes one gram (0.03 ounces) of xylitol should be treated," she said, adding that further studies were needed to definitely establish a cause-and-effect relationship.