Xylitol poisoning in dogs

Xylitol is a sugar-substitute found in lots of human sweets, medicines and gums. It’s poisonous to all dogs. Symptoms of xylitol poisoning usually develop within an hour. They can rapidly become life-threatening.

In 2020 alone, the Pet Poison Helpline received around 6000 calls from worried owners whose dogs had eaten things that contained xylitol, especially sugar-free gum. Symptoms of poisoning happen because xylitol triggers a sharp drop in blood sugar and life-threatening liver damage at high doses. Outlook depends on how much your dog has eaten and how quickly they see a vet.

Overview

Xylitol: what is it and why is it harmful to dogs?

Xylitol is a versatile ingredient. It comes in granular form, just like sugar. And so it’s used to replace sugar in low-calorie and sugar-free versions of many commercial products.

Some facts about xylitol:

Toxic to dogs if they consume 0.075-0.1 g per kg. That’s around 1g for a 10kg dog.
Contains 40% fewer calories than sugar.
Helps combat tooth decay. Xylitol prevents bacteria in the mouth from producing acid, the reverse of sugar.

Possible sources of poisoning:

Gum and sweets: a single stick of ‘sugar-free’ gum contains up to 1g of Xylitol. Enough to poison a small dog.
Granules for use in tea, coffee or baking
Cakes, puddings, biscuits, peanut butter, sugar-free jams and spreads, pie fillings
Mouthwash, toothpaste, chewable vitamins, supplements, sugar-free liquids, and dispersible medicines, such as pain-relievers (Calpol®), allergy medicines, sleeping aids, laxatives

Why is xylitol poisonous to dogs?

Xylitol triggers a sudden big increase in blood insulin levels
Blood sugar (glucose) falls sharply as insulin spikes
The more xylitol consumed for your dog’s size, the more serious the risk
Dogs who consume larger amounts of xylitol risk devastating liver damage
Both low blood sugar (hypoglycaemia) and liver damage are life-threatening
Over 62% of dogs will not survive liver disease triggered by xylitol poisoning

Symptoms

Symptoms of xylitol poisoning in dogs

Symptoms of low blood sugar develop very rapidly in xylitol poisoning – usually within 15-30 minutes of consumption. However, it may take up to 12 hours if xylitol is contained in a product that releases it more slowly (gum, for example). Ingesting 0.1g/kg or more will trigger these symptoms.

Symptoms of liver damage generally develop within 2-3 days, after ingesting 0.5g/kg or more.

Symptoms of low blood sugar

Vomiting
Weakness or unsteadiness on legs; difficulty walking or standing
Becoming extremely dull and/or sleepy
Tremors
Seizures (fits)
Coma and death

Symptoms of liver failure with xylitol poisoning

Follow on from symptoms of low blood sugar
Yellowing of gums and whites of the eyes (jaundice or icterus)
Bleeding under the skin: blood spots on gums or larger bruised areas on skin
Bleeding inside the tummy
Coma and death

Risk

Xylitol poisoning: what are the risks?

The poisoning risks of xylitol largely depend on your dog’s size and how much xylitol they eat. If a small dog and a large one eat the same amount of xylitol, symptoms will be much more severe in the small dog.

Dogs who eat over 0.1g/kg are at risk of hypoglycaemia
Dogs who eat over 0.5g/kg are at risk of serious liver damage

An example:

Half a packet of gum may contain 5 pieces. If each piece has 1g of xylitol, half a packet means 5g of xylitol.

Toxic effects of half a packet of sugar-free gum:

Small dogs, up to 10kg: life-threatening liver damage in Westie, Frenchie, Dachshund
Large dogs, 30-40kg: treatable hypoglycaemia in Rottweiler, GSD, Labrador
Giant Dogs, 60kg+: minimal or no symptoms in St Bernard, Great Dane, Bullmastiff

Dogs with existing liver disease will be less able to survive the additional damage of xylitol poisoning.

We recommend calling your vet as soon as possible if your dog has eaten anything containing xylitol.

Are all sugar substitutes and artificial sweeteners poisonous to dogs?

Steviol, malitol, sorbitol, sucralose and saccharin are not dangerous to dogs.
Very high levels of consumption may trigger tummy upsets.

Are humans or other pets at risk of xylitol poisoning?

Xylitol is not poisonous to humans. In fact, it’s widely used because of its perceived health benefits for humans.

Cats seem much less at risk of xylitol poisoning for 2 reasons – they’re not usually interested in sweet things. And xylitol does not seem to cause the same insulin surge as happens in dogs.

Diagnosis

How do vets diagnose xylitol poisoning in dogs?

Vets usually diagnose xylitol poisoning from an owners report of what their dog has eaten and the symptoms of low blood sugar. Your vet will need to run:

Blood tests: to check blood glucose levels as well as electrolytes (salts) and general organ health. Vets continue to check glucose levels every 2 hours for 12 hours
Special tests for liver damage and liver function in severe cases.

Vet treatment

How do vets treat xylitol poisoning in dogs?

There are no cures or antidotes to xylitol poisoning in dogs. And xylitol is absorbed into the body very rapidly after it’s eaten.

Vet treatment involves:

Giving your dog an injection to empty their tummy by making them sick (emesis). This can help minimise absorption of the toxin and ill effects. But it only helps if the injection is given very quickly. It’s too late if symptoms have already developed.
Admitting your dog to the clinic for intensive treatment and monitoring as an in-patient.
Giving your dog fluids containing sugar (dextrose).
Taking blood samples daily for at least 3 days to check for signs of liver damage.
Providing supportive care for dogs with liver damage: medicines to help clot blood and prevent internal bleeding.

Home treatment