Xylitol and dogs: the sweetener that can kill

The short answer

Xylitol is a sugar substitute that is highly toxic to dogs: it can make their blood sugar plummet and can damage the liver, and Blue Cross says “even small amounts can be fatal”. It is found in sugar-free chewing gum, sweets, toothpaste and some peanut butters. Signs usually start within 30 minutes but can take up to 12 hours. If your dog may have eaten anything containing xylitol, contact your vet or an out-of-hours vet now, even if your dog seems well.

This page is not veterinary advice. It sets out what Blue Cross, the PDSA and the ASPCA publish; your vet decides what your dog needs.

Where xylitol is found

Xylitol hides in products labelled sugar-free or low sugar. Blue Cross says it is “sometimes called wood sugar or birch sugar”, and the PDSA says it “may be listed as ‘birch sugar’ in the ingredients list”.

Peanut butter is the case that catches owners out. Blue Cross says a teaspoon of peanut butter “with no xylitol” is fine as a treat, so read the label every time. Sugar-free chocolate brings two risks at once: see chocolate poisoning in dogs.

How much xylitol is dangerous

Very little. Blue Cross says products “can have widely varying levels of xylitol in them, but only small amounts of the substance can cause serious harm”, and that “depending on the concentration of xylitol and the size of the dog, just one stick of chewing gum is enough to be toxic”. You cannot tell from the packet how much is too much, so treat any amount as an emergency.

Why xylitol is toxic to dogs

Blue Cross explains that a dog’s pancreas confuses xylitol with real sugar and releases more insulin. That insulin then removes the real sugar from the blood, causing hypoglycaemia, or low blood sugar. The second effect, liver failure, “is even more serious, but it’s not known what causes this to happen”. The ASPCA likewise warns of low blood sugar “and potentially liver damage depending on the amount ingested”.

Signs of xylitol poisoning, and when they start

Blue Cross lists:

• vomiting
• lethargy (tiredness)
• disorientation
• collapse
• seizures and tremors
• unconsciousness or coma

The ASPCA adds loss of coordination among the first signs, and says liver damage can lead to “abnormal bleeding”.

The timing differs between pages, so plan for the fastest:

• Blue Cross xylitol page: symptoms usually appear “within 30 minutes but can take up to 12 hours”.
• Blue Cross poisonous foods page: signs “can show within an hour, but worsen over a few days”.
• ASPCA: “liver damage can occur within 12-24 hours”.

What to do if your dog ate xylitol

1. Get your dog to a vet straight away. Blue Cross says this is urgent “as it can be absorbed into the blood stream rapidly”, and that you should “never wait for symptoms to appear”. If your practice is closed, go to an out-of-hours vet.
2. Take the packaging with you. Blue Cross asks owners to bring it “wherever possible”, so the vet can see what was eaten.
3. Do not make your dog sick at home. Only a vet should decide whether to do this.

What the vet may do

Blue Cross says that if the dog arrives early enough, the vet “may be able to induce vomiting”. The dog is then likely to go on a sugar drip into the vein to regulate blood sugar and be closely monitored for two to three days. If the liver is affected, “it’s far more serious and will normally require specialist lifesaving treatment”. Speed matters: if the drop in blood sugar is prevented or controlled quickly, “the prognosis is good”.

Keeping xylitol away from your pets

Blue Cross advises making sure “no packs of chewing gum are left lying around the home or kept in pockets and handbags that your pet can raid”, and says xylitol “can be toxic to other animals” too. The same habit of keeping human food out of reach protects against grapes and raisins, and cat owners should also know about lilies and onions and garlic.

Before you act

Read the Blue Cross xylitol page, reviewed by a veterinary surgeon, and check the ingredients of anything sugar-free in your home. If your dog may already have eaten some, get to a vet before you read anything else.