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What is xylitol and is it poisonous?

Xylitol is a commonly used artificial sweetener and appears to be harmless to humans (there is no evidence of any harm from eating it in moderation). However, in dogs, it is potentially fatal poison, with as little as 0.1g (100mg) per kg bodyweight being dangerous.


What is xylitol?

Xylitol is a “sugar alcohol”, meaning its chemical structure is similar but not identical to sugar. The similarities are enough to “trick” our taste-buds, being as sweet as sugar but having only about ⅔ the calories - hence its use as a sweetener. It also inhibits bacterial growth and is found in many dental products to reduce plaque and bacterial growth in the mouth.


What is it found in?

It’s widely used in medicines, dental products, and “low-sugar” baking and foods. However, the majority of poisonings come from the ingestion of sugar-free gum, which tastes sweet and often has a relatively high concentration of xylitol (reportedly up to 2000mg per stick).


What are its effects on a dog’s the body?

Blood sugar in dogs, just like people, is regulated by the pancreas. As the blood sugar rises, the pancreas releases insulin to lower it (this is the system that fails to operate in diabetic people and animals). In humans, the pancreas is more sensitive than the taste buds and can distinguish between xylitol and sugar; however, the dog’s pancreas cannot. As a result, as blood xylitol levels rise, the dog’s pancreas thinks the blood sugar is too high and releases extra insulin - even though blood sugar is perfectly normal. As a result, their blood sugar level crashes and the dog becomes hypoglycaemic.

The symptoms of this usually start within an hour, although can occasionally be delayed, and typically include:

  • Sudden onset vomiting
  • Altered behaviour
  • Weakness and wobbliness, progressing to inability to stand
  • Depression and altered heartbeat
  • Seizures, coma and ultimately death if severe and untreated

However, we now know that high doses of xylitol can cause poisoning through a second mechanism as well, causing severe liver damage. This takes a little longer, with clinical signs appearing at one to two days after eating the substance. Because the liver is so important to life, this is frequently fatal, with symptoms including:

  • Depression and lethargy
  • Vomiting and diarrhoea
  • Jaundice (yellow gums and eyes)
  • Abnormal clotting, resulting in bleeding from the nose, mouth and anus, rashes on the skin and gums, and sometimes internal haemorrhage
  • Death follows several days later in most cases unless treatment is started early


Can it be treated?

The drop in blood sugar levels can be managed with intensive care nursing and intravenous fluids such as a sugar drip; however, if the brain is starved of glucose for too long, it can be fatal, so early treatment is essential.

The liver damage is much harder to manage, but hospitalisation, intensive and aggressive treatment may be successful.


How serious is it?

The majority of dogs with hypoglycaemia (low blood sugar) as their only problem will survive, with rapid treatment. However, studies suggest that if liver failure occurs, only about one dog in three will recover, even if given every available treatment.


What is a dangerous dose?

For hypoglycaemia, about 100mg/kg (so roughly 1 stick of gum per 10-20kg of body weight). Liver failure tends to be seen above about 500mg/kg (i.e. approximately 1 stick of gum per 2-4kg bodyweight). As dogs often eat whole packs (10-40 sticks), poisoning is a very real threat!


Are cats or other animals at risk?

While it is not known whether xylitol is dangerous to cats, we would strongly advise not giving the substance to cats if possible!


How can I keep my dog safe?

Basically, keep xylitol away from them. If you’re taking any medications or using dental products containing the substance or using it in cooking, or chewing gum - make sure that your dog never has access!

This is also one reason you should NEVER use human medicines to treat your dog unless prescribed by a vet because so many of them contain this substance. Note, however, that there is one veterinary product that does contain xylitol (it’s a dog mouthwash) - however, it has been specially formulated for dogs, and contains so little that if you mix it up with the water to the correct proportions, there’s no risk of poisoning.


If you are concerned your dog may have eaten something they shouldn’t, call us immediately!

Rushcliffe Vets
Rushcliffe Vets
What is xylitol and is it poisonous?