Chocolate gets all the attention. Xylitol is worse, and most owners have no idea how many products in their house contain it.
What it does
Xylitol is a sugar alcohol used as a sweetener. In humans it has no meaningful effect on insulin.
In dogs it does something entirely different. It triggers a rapid, massive release of insulin from the pancreas, which causes blood sugar to crash — profound hypoglycaemia, within as little as 10 to 60 minutes of ingestion, though it can be delayed by up to 12 hours with some slower-release products such as chewing gum.
At higher doses it causes acute liver failure, which may develop over 24 to 72 hours and can occur even in dogs who did not show hypoglycaemia.
The toxic dose is very low. Hypoglycaemia can occur at around 0.1g per kilogram of body weight, and liver failure at around 0.5g/kg. A single piece of some sugar-free gums can contain enough to cause hypoglycaemia in a small dog.
The naming problem
Xylitol is not always labelled clearly. Watch for:
- Xylitol
- Birch sugar or birch sap sugar — increasingly common on “natural” products
- Wood sugar
- E967
- “Sugar-free” or “no added sugar” as a general warning to check the ingredients
- “Sweetened with sugar alcohols”
Note that not all sugar alcohols are dangerous. Erythritol, sorbitol and maltitol do not have the same effect in dogs. Xylitol is specifically the problem, which is why reading the actual ingredient name matters.
Where it hides
The obvious:
- Sugar-free chewing gum — the most common source of poisoning cases
- Sugar-free mints and sweets
- Sugar-free chocolate
The less obvious:
- Peanut butter. Some brands use it. This one causes the most cases, because peanut butter is what people stuff food toys with. Check every jar, every time — brands reformulate
- Protein bars and meal replacement bars
- “No added sugar” baked goods, jams and syrups
- Some breakfast cereals
- Sugar-free jelly and desserts
- Toothpaste and mouthwash
- Some children’s medicines, particularly liquid ones
- Chewable vitamins and supplements
- Nasal sprays
- Some nicotine gums and lozenges
- Sugar-free drinks powders
- Some cosmetics and skin products
Signs of poisoning
Hypoglycaemia, usually within an hour:
- Weakness, wobbliness, stumbling
- Vomiting
- Lethargy or collapse
- Tremors
- Seizures
Liver injury, over 24 to 72 hours:
- Vomiting, lethargy, loss of appetite
- Jaundice — yellowing of the gums, eyes or skin
- Abnormal bleeding or bruising
- Dark urine
What to do
This is an emergency. Ring your vet immediately — do not wait for symptoms.
- Work out, as accurately as you can, how much was eaten and when
- Take the packaging. The xylitol content is what determines the treatment
- Do not induce vomiting unless a vet instructs you to
- If your dog is already showing signs of hypoglycaemia and is conscious and able to swallow, a vet may advise rubbing a small amount of honey or glucose syrup onto the gums on the way in. Only on veterinary instruction, and never in a dog who is unconscious or seizing
- Go
Treatment
Depending on timing and dose:
- Induced vomiting, if very recent
- Activated charcoal does not bind xylitol well, so it is not a reliable measure here
- Intravenous dextrose to maintain blood glucose, often for 12 to 24 hours or longer
- Blood glucose monitoring, frequently
- Liver function monitoring for several days
- Liver protectants, and supportive care
- Plasma or blood products if clotting is affected
Prognosis is good for dogs treated promptly for hypoglycaemia alone. It is considerably worse once liver failure has developed — which is precisely why the advice is to ring before symptoms appear rather than after.
Prevention
- Read every peanut butter label, and re-read it when you buy a new jar
- Keep handbags off the floor. Gum in a bag is the classic scenario
- Store all sugar-free products in closed cupboards
- Keep toothpaste, mouthwash and medication in a cabinet
- Tell visitors, especially anyone who chews gum
- Tell children not to share sugar-free sweets with the dog
- Check supplements and chewable vitamins
- Never use human toothpaste on a dog
The peanut butter rule
Peanut butter is one of the most useful things in a dog owner’s cupboard — for stuffing food toys, for lick mats, for hiding tablets, for making grooming and nail trims tolerable.
It is worth buying one specific jar, checking it carefully, and keeping it separate from the family’s. Write “dog” on it.
A single jar of the wrong peanut butter, used to stuff a food toy, has killed dogs. It is the most preventable poisoning there is, and it takes fifteen seconds of label reading to prevent.
And one more time, because it is the point
If you think your dog has eaten anything containing xylitol, ring your vet immediately. Not in the morning, not after seeing whether they seem unwell. Now.
Hypoglycaemia can begin within ten minutes, and the dogs who do badly are almost always the ones who arrived late.
