Xylitol toxicity in dogs: work out the dose, then call
If your dog has eaten anything sugar-free, call your vet or an animal poison helpline now — the numbers are at the top of this page. This xylitol toxicity calculator helps you tell them how serious it might be: it turns the xylitol content on the label and the amount eaten into a dose in milligrams per kilogram of your dog’s weight, and compares it with the levels in the Merck Veterinary Manual.
Xylitol is a sugar alcohol used in sugar-free gum, mints, some peanut and nut butters, baked goods, toothpaste, chewable vitamins and liquid medicines. In dogs it causes a rush of insulin and a sudden drop in blood sugar, and at higher doses it can destroy the liver. Small dogs can be poisoned by just a few pieces of gum.
The calculator has no built-in product values on purpose: the amount of xylitol varies between products and even flavours. Read the label, and if you cannot find the number, tell your vet exactly what was eaten and bring the packet.
How to use the Xylitol Toxicity Calculator
- Enter your dog’s weight in kg or lb.
- Choose what was eaten and how the label shows the xylitol: per piece, per 100 g, pure xylitol or a total in mg.
- Enter the xylitol per piece or per 100 g from the label and the amount eaten — assume the most it could have been.
- Read the dose in mg/kg, the risk band and how much of this product reaches each level.
- Call your vet or a poison helpline with the product, the amount, the time and your dog’s weight.
Xylitol Toxicity Calculator features
Vet-reference levels
100 mg/kg for low blood sugar and 500 mg/kg for liver failure, from the Merck Veterinary Manual (ASPCA author).
Any label format
Per piece, per 100 g, pure xylitol or a known total.
Threshold amounts
How many pieces or grams of this product reach each level for your dog.
Animated severity meter
A marker on a 0–600 mg/kg scale coloured by the published bands.
Helplines always visible
US and UK animal poison lines at the top of the page.
Xylitol dose levels in dogs
Source: Merck Veterinary Manual, “Xylitol Toxicosis in Dogs” (Cristine Hayes, DVM, ASPCA Animal Poison Control Center; reviewed September 2024, updated June 2025; checked October 2026). Low blood sugar can start within 30 minutes, or 12–18 hours later when gum slows absorption. Liver damage may not show for 24–48 hours, so a dog that seems fine can still be in danger.
Example: a 10 kg dog eats 4 pieces of gum labelled 0.5 g of xylitol each. 4 × 0.5 g = 2 g = 2,000 mg; ÷ 10 kg = 200 mg/kg — above the hypoglycaemia level. Activated charcoal does not bind xylitol well, and home-induced vomiting is not recommended — leave treatment to your vet.
| Dose | In a 10 kg dog | What is reported |
|---|---|---|
| Above about 100 mg/kg (45 mg/lb) | 1 g of xylitol | Low blood sugar (hypoglycaemia): vomiting, weakness, wobbling, collapse, seizures |
| Above 500 mg/kg (227 mg/lb) | 5 g of xylitol | Severe liver injury or failure in some dogs, sometimes with bleeding problems |
Xylitol in cats, other pets and people
Cats: the Merck Veterinary Manual states that cats are not at risk of the hypoglycaemia or liver injury seen in dogs, and dogs are the only domestic species in which xylitol poisoning has been reported. The FDA notes that ferrets can develop low blood sugar and seizures, so call your vet for any pet that eats a sugar-free product.
People: according to the FDA, xylitol does not trigger insulin release in humans the way it does in dogs, which is why it is used as a sugar substitute. In large amounts it mainly causes wind and diarrhoea. It may appear on labels as “birch sugar” or “wood sugar”.
Where xylitol hides
Check our toxic foods for pets checker for other dangerous foods, and the chocolate toxicity calculator if chocolate was involved.
- Sugar-free gum, breath mints and sweets — the most common cause of poisoning.
- Some peanut and nut butters, sugar-free jams, baked goods and “skinny” ice creams.
- Toothpaste and mouthwash (never use human toothpaste on dogs).
- Chewable vitamins, supplements, cough syrups and liquid medicines.
Xylitol Toxicity Calculator FAQ
How much xylitol is toxic to a dog?
The Merck Veterinary Manual links doses above about 100 mg per kg (0.1 g/kg) to low blood sugar and above 500 mg/kg (0.5 g/kg) to liver failure in some dogs. For a 10 kg dog that is about 1 g and 5 g of xylitol.
My dog ate sugar-free gum. What should I do?
Call your vet or an animal poison helpline immediately, with the packet. Do not wait for signs — low blood sugar can start within 30 minutes and liver damage may not show for a day or two.
How do I find the xylitol content?
Look on the nutrition panel for “xylitol” in grams per piece or per 100 g. If only “sugar alcohols” or “polyols” is given, use that as a worst case and tell your vet.
Is xylitol toxic to cats?
Merck says cats are not at risk of the low blood sugar or liver injury seen in dogs. Still call your vet if your cat eats a sugar-free product, especially one with other ingredients.
Is xylitol toxic to humans?
No, not in the same way. The FDA says it does not stimulate insulin release in people; large amounts can upset the stomach.
Is this calculator a substitute for a vet?
No. Ask your vet — this is general information, not veterinary advice.