Xylitol and dogs: why it is so dangerous and where it hides
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
If your dog has swallowed “sugar-free” gum, a sweet, toothpaste or peanut butter, call your vet or an animal poison helpline straight away, even if your dog seems perfectly well — in the US the ASPCA Animal Poison Control Center, (888) 426-4435 (a consultation fee may apply), in the UK Animal PoisonLine, 01202 509 000, in France the CNITV in Lyon, 04 78 87 10 40. Keep the packaging: you will be asked whether xylitol is on the ingredient list, and where. Do not make your dog vomit yourself, with salt or hydrogen peroxide: with xylitol a dog can collapse within tens of minutes, and vomiting should only be induced under veterinary supervision. Treated early, the vast majority of dogs do well.
Contents · 7 sections
What xylitol does to a dog
Xylitol is a sugar alcohol, a sweetener also sold as birch sugar or listed as E967. In people it barely affects insulin. In dogs it triggers a rapid, massive release of insulin that makes blood sugar crash. According to the Merck Veterinary Manual, low blood sugar has been reported above about 100 mg of xylitol per kilo of body weight (45 mg per pound), and severe liver injury in some dogs above 500 mg/kg (227 mg per pound). Signs of low blood sugar can appear within 30 minutes, or up to 12 to 18 hours later when the xylitol is in a gum that slows its absorption. Signs of liver injury often come 24 to 48 hours later. Cats are not affected.
Table: thresholds by your dog’s weight
We multiplied the two Merck Veterinary Manual thresholds by body weight. The amount of xylitol per piece of gum or per spoonful varies widely between brands and is not always printed, which is why your vet or the poison line needs the packaging.
| Dog’s weight | Low blood sugar threshold (100 mg/kg) | Liver injury threshold (500 mg/kg) |
|---|---|---|
| 3 kg (6.6 lb) | 0.3 g | 1.5 g |
| 5 kg (11 lb) | 0.5 g | 2.5 g |
| 10 kg (22 lb) | 1 g | 5 g |
| 20 kg (44 lb) | 2 g | 10 g |
| 30 kg (66 lb) | 3 g | 15 g |
| 40 kg (88 lb) | 4 g | 20 g |
How to read it: for a 5 kg (11 lb) dog, half a gram of xylitol is enough to raise concern about low blood sugar. For a small dog the margin is very thin, which is why you should always call.
Where xylitol hides
The Merck Veterinary Manual’s list is longer than most people expect:
- “Sugar-free” confectionery: chewing gum, sweets, mints, diet chocolate and baked goods.
- Peanut butters and spreads with “no added sugar”: check before filling a toy or a lick mat.
- Human oral care: toothpaste, mouthwash, flavoured floss and dental sticks. Never use your own toothpaste on your dog; our guide to dog dental care explains what to use instead.
- Chewable medicines and supplements: gummy vitamins, lozenges, sugar-free syrups (some human liquid gabapentin solutions contain it, the Merck notes).
- Unexpected products: some sunscreens, cosmetics and deodorants.
Handbags, coat pockets and bedside tables are where dogs find them most often.
What the studies show
The study by Dunayer and Gwaltney-Brant, published in 2006 in the Journal of the American Veterinary Medical Association, was the first to describe liver failure after xylitol: of eight dogs, five had bleeding, and five died or were euthanised (see the study). More recent data are more reassuring when care is prompt. A study by Lovell and colleagues, published in 2025 in the Journal of Veterinary Emergency and Critical Care, followed 95 dogs brought in after eating xylitol: about half showed some liver injury, none developed liver failure. Dogs already showing signs on arrival were 1.95 times more likely to develop liver injury, and dogs in which the vet induced vomiting were less likely to (see the study). A review by Murphy and Dunayer published in 2018 sums it up: the outlook is generally good when low blood sugar is uncomplicated (see the study).
Signs to watch for
- Low blood sugar (30 minutes to a few hours): vomiting, weakness, wobbly gait, lethargy, trembling, seizures, even coma.
- Liver injury (often after 24 to 48 hours): lethargy, vomiting, yellow gums or eyes, bleeding or small red spots on the skin.
- Even with no signs at all, the vet may keep your dog in to check blood sugar at regular intervals and liver enzymes over the following days.
Prevention
- Read the label of anything “sugar-free” before sharing it: xylitol, birch sugar, E967.
- To fill a toy, choose a peanut butter whose only ingredient is peanuts (perhaps with salt); our filling ideas are in the lick mat guide.
- Keep bags and coats up high, especially when you have guests.
- For other risky foods, our dog food page gathers our guidance.
Frequently asked questions
My dog ate a piece of gum. Is it serious?
It depends on whether it contains xylitol, how much, and your dog’s weight. Gum without xylitol is mainly a digestive risk; with xylitol, a small dog can be in danger. Call with the packet in hand: the vet does the maths.
How long after eating xylitol does a dog get sick?
Low blood sugar can start within 30 minutes, sometimes as late as 12 to 18 hours with gum. Liver injury tends to show 24 to 48 hours later, which is why blood tests matter even if the dog seems fine.
Are other sweeteners dangerous?
The serious poisonings documented in dogs involve xylitol. A “sugar-free” product may, however, contain it alongside another sweetener: read the whole ingredient list, and when in doubt, call.
Is xylitol dangerous for cats?
No, according to the Merck Veterinary Manual: cats do not develop the low blood sugar or liver injury seen in dogs. Dogs are the only domestic species affected.
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This guide is part of Planète Pets’s Dogs universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.
