The Full Story
Xylitol is found naturally and is commonly extracted from birch or corncobs to be used as a sweetener in commercial products like gum, candy, baked goods and toothpaste. Although well tolerated in humans, the sugar substitute xylitol can be poisonous to dogs.
When swallowed by canines, xylitol absorption is rapid. Vomiting can be seen in only 30 minutes, but full symptoms can be delayed for up to 12 hours. In dogs xylitol stimulates insulin secretion and can lead to profoundly low blood sugar; this causes weakness and loss of coordination. If left untreated, dogs may eventually develop seizures or collapse. With large ingestions xylitol has also been linked to liver failure in dogs.
In humans, xylitol is slowly absorbed and causes little insulin release. It contains fewer calories than sugar and has the added benefit of preventing oral bacteria and cavities. In people who swallow large quantities, though, xylitol causes mild adverse effects including diarrhea or flatulence.
Amanda McDaniel-Price, RN, BA, BSN
Certified Specialist in Poison Information
Dunayer EK. New findings on the effects of xylitol ingestion in dogs. Veterinary Medicine. 2006;December:791-797.
Murphy LA, Coleman AE. Xylitol toxicosis in dogs. Vet Clin Small Anim. 2012;42:307–312. doi:10.1016/j.cvsm.2011.12.003
Academy of Nutrition and Dietetics. Position paper: use of nutritive and nonnutritive sweeteners. J Acad Nutr Diet. 2012;112:739-758.
Store items with xylitol where pets can't reach them. Examples include some foods, chewing gum, and toothpaste.
This Really Happened
A 4-year-old male dog was evaluated at a veterinary emergency clinic for sudden onset of lethargy. Approximately 1 to 2 hours earlier, the dog had eaten 4 large frosted muffins sweetened with xylitol. The dog was extremely lethargic on examination. His blood glucose level was very low. The dog was given intravenous (IV) dextrose and IV fluids. Two hours later, his blood glucose remained dangerously low and he was given additional IV dextrose. His blood glucose briefly improved but five hours after ingesting the xylitol, fell again. The dog began vomiting. The day after the ingestion, the dog's blood glucose remained very low and he was again given IV dextrose. He was transferred to a specialty veterinary clinic. He was bleeding from the nose, mouth and bowel. His blood cell counts and blood clotting studies were abnormal and he was treated with transfusions. The dog became progressively more lethargic and had a seizure. On the 3rd day after the xylitol ingestion, the dog's condition worsened. His heart rate was extremely elevated, he developed a temperature of 106 degrees Fahrenheit and he had trouble breathing. His blood pressure plummeted. He then vomited a large amount of blood. Because of the dog's rapidly deteriorating condition, his owner permitted euthanasia. Autopsy findings were consistent with ingestion of an agent toxic to the liver. Widespread hemorrhage was seen in the kidneys, stomach, small intestine, pancreas, heart muscle and lymph nodes.
Reference: Dunayer, E.K., & Gwaltney-Brant, S.M. (2006). Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs. Journal of the American Veterinary Medicine Association (229) 7, 1113-1117.