Why xylitol is so dangerous for dogs
Xylitol is a sugar substitute. In people it barely affects blood sugar, but in dogs it triggers a large release of insulin. Blood sugar then drops sharply, sometimes within half an hour, which can cause weakness, wobbling, seizures and coma. At higher doses xylitol can also destroy liver cells, and some dogs develop liver failure a day or two later.
How the calculator works
The calculator multiplies the grams of xylitol per piece by the number of pieces, converts to milligrams and divides by your dog's weight:
dose (mg/kg) = grams per piece × pieces × 1000 ÷ dog's weight in kg
dose (mg/lb) = the same with the weight in lb
Example: a 20 lb (9.1 kg) dog eats 2 pieces of gum with 1 g of xylitol each. 2 g = 2000 mg, and 2000 ÷ 9.1 ≈ 220 mg/kg (about 100 mg per lb). That is above the 100 mg/kg level where low blood sugar is expected, so the dog needs a vet now.
The amount of xylitol differs widely between brands and even between flavors of the same gum, which is why the calculator asks for the label value instead of using an average.
Toxic dose levels
| Dose per lb | Dose per kg | What to expect |
|---|---|---|
| Above 45 mg/lb | Above 100 mg/kg | Low blood sugar (hypoglycemia): vomiting, weakness, wobbling, seizures. Vets hospitalize from this dose. |
| Above 227 mg/lb | Above 500 mg/kg | Liver damage and possible liver failure in some dogs, in addition to low blood sugar |
How much xylitol by dog weight
| Dog's weight | Low blood sugar above | Liver risk above |
|---|---|---|
| 5 lb (2.3 kg) | 0.23 g | 1.1 g |
| 10 lb (4.5 kg) | 0.45 g | 2.3 g |
| 20 lb (9 kg) | 0.9 g | 4.5 g |
| 40 lb (18 kg) | 1.8 g | 9.1 g |
| 60 lb (27 kg) | 2.7 g | 13.6 g |
| 80 lb (36 kg) | 3.6 g | 18.1 g |
| 100 lb (45 kg) | 4.5 g | 22.7 g |
Grams of xylitol, not grams of the product. Thresholds of 100 and 500 mg/kg from the Merck Veterinary Manual.
Products that can contain xylitol
- Sugar-free gum, candy, mints and breath fresheners
- Some peanut butters and other nut butters, and sugar-free baked goods
- Toothpaste, mouthwash and other oral care products
- Chewable or gummy vitamins and supplements
- Some liquid medicines and syrups, including some made for people
- Sunscreens, cosmetics, deodorants and hair care products
Before giving your dog peanut butter or a human vitamin, read the ingredient list.
Signs of xylitol poisoning in dogs
| Time after eating | What you may see |
|---|---|
| From 30 minutes (up to 12–18 hours with some gums) | Low blood sugar: vomiting, weakness, wobbling, lethargy, seizures, coma |
| 24–48 hours or more | Liver damage: lethargy, vomiting, yellow gums or eyes, bleeding or bruising |
What to do if your dog ate xylitol
- Take away the rest and keep the package: the label tells the vet how much xylitol there was.
- Call your vet, an emergency vet or a poison hotline right away. Low blood sugar can start before you reach the clinic.
- Do not induce vomiting at home unless a vet tells you to. Vomiting should be induced under veterinary supervision.
- If the vet asks you to come in, go right away.
At the clinic, a vet may make a dog that still seems normal vomit. Activated charcoal does not bind xylitol well, so it is not normally used. Dogs above 100 mg/kg are usually hospitalized, with blood sugar checks every 1 to 2 hours for at least 12 hours and sugar (dextrose) through a drip when needed. Liver values are checked daily for at least 3 days after higher doses. With prompt treatment the outlook for low blood sugar alone is good; once liver failure develops it is guarded.
Frequently asked questions
How much xylitol is toxic to dogs?
According to the Merck Veterinary Manual, more than about 100 mg of xylitol per kg of body weight (45 mg per lb) can cause dangerously low blood sugar, and more than 500 mg/kg (227 mg per lb) can cause liver failure in some dogs. For a 20 lb dog that is about 0.9 g and 4.5 g of xylitol.
My dog ate sugar-free gum. What should I do?
Check the label for xylitol, then call your vet, an emergency vet or a pet poison hotline right away: ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661. Xylitol content differs widely between brands and flavors, so bring the package. Do not make your dog vomit unless a vet tells you to.
How fast does xylitol affect dogs?
Low blood sugar can start within 30 minutes. With some chewing gums it can be delayed by 12 to 18 hours because the gum releases xylitol slowly. Signs of liver damage appear 24 to 48 hours or more after eating.
Which products contain xylitol?
Sugar-free gum, candy and mints, some peanut butters and baked goods, toothpaste and other oral care products, chewable or gummy vitamins and supplements, some liquid medicines, sunscreens, cosmetics and hair care products. Always check the ingredient list.
Is xylitol toxic to cats?
According to the Merck Veterinary Manual, dogs are the only domestic species with reported xylitol poisoning, and cats are not considered at risk. Keep xylitol products away from dogs in particular.
Sources
- Merck Veterinary Manual: Xylitol Toxicosis in Dogs (dose thresholds, products, onset of signs, treatment and prognosis).
- VCA Animal Hospitals and Pet Poison Helpline: xylitol product lists and onset of signs.
- ASPCA Animal Poison Control Center and Pet Poison Helpline (contact numbers, checked October 2026).
This calculator is for general information only and does not replace a veterinarian. Product labels can be incomplete, dogs react differently, and a low estimate does not mean your dog is safe. If your dog ate xylitol, contact a vet or a pet poison hotline. Last updated: October 2026.