What is xylitol, and how toxic is it to dogs? What are the symptoms of xylitol poisoning?

Dr. Laura O'Rourke DVM
sponsored by Ann Arbor Animal Hospital

We recently had several dogs come into our emergency facility with symptoms of toxicity. The culprit? Xylitol, a sugar substitute found in sugarless gums, candies and even snacks like cookies, cakes and ice cream.

Most people have heard that chocolate is poisonous to dogs. They may not know the reason—dogs are sensitive to the caffeine-like effect of methylxanthine in chocolate—but chocolate is kept away and dogs stay healthy. Xylitol is even more toxic and should be added to the list of forbidden foods for dogs.

Xylitol is a sugar alcohol found naturally in the fibers of many plants. It is used commercially as a sweetener in place of sugar and has approximately the same sweetness, and is available in granulated form for home use. It has become popular among people with diabetes because it is absorbed more slowly than sugar and doesn’t cause significant changes in insulin levels the way sugar does. Because studies have shown that it helps prevent cavities in teeth, xylitol is most commonly used as a sweetener in chewing gums and is added to oral care products like toothpaste and mouthwash.

Unfortunately, though it can be beneficial to humans, xylitol is not processed at all the same way when consumed by dogs. Unlike with people, a dog’s body absorbs xylitol very rapidly into the bloodstream, where it stimulates the release of a large amount of insulin, which in turn causes extreme hypoglycemia, or low blood sugar. Hypoglycemia can cause liver failure, bleeding, and ultimately death. It can only take a little bit of xylitol, say one piece of gum or one cupcake, to cause visible signs of low blood glucose:

The first symptom is usually vomiting, or collapse.

Hypoglycemia can come on quickly, causing lethargy and loss of coordination.

Diarrhea and seizures are possible.

If your dog ingests xylitol, it should be immediately taken to a veterinarian. The vet will need to know what the xylitol was in and how much was consumed—if you aren’t sure, estimate on the high side. With prompt attention, treatment can be as simple as inducing vomiting, and chances of recovery can be very good. More severe cases may require administration of dextrose to prevent hypoglycemic shock, followed by treatment for liver disease.

Remember that just because foods are okay for people to eat, the same may not be true for the animals we keep, especially as we manufacture and modify more products for human consumption. Also remember to read the labels on food, but keep in mind that all the information you’re looking for may not be provided. You don’t have to avoid products that contain xylitol, but be sure to store them where your dog cannot get to them—next to your stash of chocolate might be a good place. Be sure to share this information with your kids too, as they often give dogs “unauthorized” snacks. As with so many health issues, prevention is much better than treatment.

Laura O'Rourke, DVM, is a graduate from the College of Veterinary Medicine at MSU. She has practiced at the Ann Arbor Animal Hospital since 2006. Her veterinary interests are in dermatology, internal medicine and soft tissue surgery.