Blog/Nutrition

Xylitol poisoning in dogs: how much is dangerous

Updated August 2, 2026·4 min

DOG · XYLITOL

Xylitol harms dogs at amounts too small to look like a portion. Blood sugar starts falling above 100 mg per kilogram of body weight, which is 0.5 g in a 5 kg dog. Above 500 mg/kg the liver takes the hit, or 2.5 g in that same dog. Signs can start within half an hour or hold off for 12–18 hours, and liver failure shows only after a day or two. The call is made on the amount eaten, whatever the dog looks like in the first hours.

01How much xylitol is dangerous

Dog’s weight

Blood sugar (>100 mg/kg)

Liver damage (>500 mg/kg)

5 kg

0.5 g

2.5 g

10 kg

1 g

5 g

20 kg

2 g

10 g

Half a gram does not look like a serving and barely registers as weight, yet in a 5 kg dog it is enough to send blood sugar down. Vets call that hypoglycaemia. How much xylitol sits in one stick of gum is rarely something the pack will tell you, so the dangerous amount is counted in milligrams per kilogram of body weight.

The timing is the second trap. Sugar starts dropping around 30 minutes in, but the drop can be delayed by 12–18 hours. Liver enzymes rise within 4–12 hours, while liver failure itself becomes visible only after 24–48. The FDA puts the start of poisoning within 20 minutes: vomiting, low activity, weakness and collapse, a staggering walk, tremors or seizures.

The outlook depends on how far things went. A sugar crash treated quickly carries a good prognosis. Once liver injury is established the figures change: 62.5% of dogs died or were euthanised despite intensive treatment.

02Where xylitol hides

Sugar-free gum, sweets and breath mints — the most common source of all.
Peanut and nut butters: these are handed to dogs on purpose, so read the jar first.
Cough syrups and liquid medicines — the manual names gabapentin syrup in particular.
Toothpaste, mouthwash, chewable vitamins and supplements.
Sunscreens and cosmetics, deodorants, hair products, nasal sprays.
Home baking made with a sugar substitute.

The front of the pack often carries no mention of xylitol at all. The FDA lists the other names the same substance goes by (wood sugar, birch sugar and birch bark extract), and European ingredient lists may show it as the additive E967. Different word, same thing. The other foods toxic to dogs have a list of their own.

03Cats are not at risk from xylitol

This is where the internet warns wider than the source does. The Merck veterinary manual says it plainly: dogs are the only domestic species in which xylitol poisoning has been reported, and cats face no risk of low blood sugar or liver injury from it. That statement covers xylitol and nothing else: onion and garlic, for one, hit cats harder than dogs.

04What to do if your dog ate some

Call your own clinic, or the nearest 24-hour one, before any signs appear.
Take the packaging with you: without the ingredient list there is no dose per kilogram.
Give the time it happened: that decides whether vomiting is still worth inducing.
In the US, Pet Poison Helpline (855-764-7661) and ASPCA APCC (888-426-4435) take calls.
Salt, ipecac syrup and fingers down the throat are listed as the wrong kind of help.

Vomiting at home is allowed by the manual in one narrow case: a dog, 3% hydrogen peroxide at 1–2 ml per kilogram, no more than 45 ml, and only where veterinary care cannot be reached. A dog that is dull, unsteady or swallowing badly is not made to vomit at all. From there it runs as with a dog that ate chocolate: dose per kilogram, timing, a vet watching.

Platera keeps a record of the episode

Sugar falls within half an hour and the liver answers a day later. The vet needs the date, the time and what went in.

Platera9:00 AM

Mia’s booster shot is tomorrow — clinic at 12:00

Point your camera · App Store

05Frequently asked

My dog ate sugar-free gum — what should I do?

Call a vet straight away instead of waiting for symptoms: blood sugar can start dropping within half an hour, while the liver only answers after a day or two. Bring the packaging with you. How much xylitol one stick holds is not something a label tells you, so the risk is counted in milligrams per kilogram of body weight, and counting sticks gets you nowhere.

How long does xylitol poisoning take to show?

Blood sugar starts falling around 30 minutes after eating, though the drop can be delayed by 12–18 hours. Liver enzymes rise within 4–12 hours and liver failure becomes visible only after 24–48. The FDA says poisoning can begin within 20 minutes, with vomiting, low activity, weakness, a staggering walk, tremors or seizures.

Is xylitol dangerous for cats?

No. The Merck veterinary manual states that dogs are the only domestic species in which xylitol poisoning has been reported, and that cats are not at risk of low blood sugar or liver injury from it. That applies to xylitol specifically: onion and garlic, for one, hit cats harder than dogs.

What else is xylitol called on labels?

The FDA lists wood sugar, birch sugar and birch bark extract as other names for the same sweetener, and European ingredient lists may show it as the additive E967. Reading the full ingredient list is the only check that works, because the front of the pack usually says no more than sugar-free.

Is peanut butter safe for dogs?

Peanut butter is not the problem in itself: xylitol is added to some brands as a sweetener, and the front of the jar does not show it. Read the whole ingredient list and look for xylitol, wood sugar or birch sugar. If a jar like that lives in the house, keep it where the dog cannot reach it.

Sources

FDA — Paws Off! Xylitol is Toxic to Dogs↗

Merck Veterinary Manual — Food Hazards↗