Can dogs eat xylitol (birch sugar)?

Why

Xylitol is a sugar alcohol used to sweeten things without the sugar. In people it passes through fairly quietly and barely nudges insulin. A dog's pancreas reads it completely differently: it mistakes xylitol for real sugar and releases a surge of insulin when there is no actual sugar coming in to balance it. Blood glucose then falls hard and fast. This often begins within half an hour to an hour of eating it, though some chewing gums release xylitol more slowly and signs can be delayed for several hours, which is exactly why a dog who seems fine is not evidence that nothing is happening.

Low blood sugar is the immediate danger, because the brain runs on glucose. That is what produces the wobbliness, tremors, collapse and seizures owners describe. On top of that, larger exposures can cause acute liver injury. The liver damage can appear without any preceding low blood sugar, and it can show up a day or two later, sometimes with problems in the blood's ability to clot. So there are two separate clocks running, and neither of them is something you can watch from home.

What makes it worse is size and formulation. A small dog needs far less to get into trouble than a large one, and xylitol in gum, mints, liquid medicines or a soft spread is absorbed quickly. What makes it better is speed. Dogs treated early, before the crash, generally do far better than dogs brought in once they are already collapsing, because a vet can monitor glucose, support it with a drip and protect the liver rather than chase a crisis that has already started. Nothing you can do at home changes the chemistry. Getting to a vet quickly changes the outcome.

Is any amount safe?

There is no established safe amount of xylitol for a dog, and you should not try to work one out. Products almost never state how much xylitol they contain, the concentration varies enormously between one sugar-free peanut butter or gum and another, and individual dogs differ in how strongly they react, so the amount that leaves one dog unscathed may badly hurt another of the same size. A single piece of gum from a coat pocket can matter for a small dog. This is the one category where "he only had a little bit" is not reassurance, it is a reason to ring your vet and let them do the maths with you.

Signs to watch for

• Vomiting, often the first thing owners notice
• Sudden lethargy or weakness, as though the energy has drained out of them
• Wobbliness, stumbling or a drunk-looking walk
• Trembling or shaking
• Collapse or seizures
• Later on, sometimes a day or two after: yellowing of the gums or the whites of the eyes, easy bruising, and going off food

Keeping it out of reach

• Read labels for xylitol, birch sugar, wood sugar or E967, and treat any product marked sugar-free, tooth-friendly or keto as suspect until you have checked the ingredients.
• Check the jar before you use peanut butter for a stuffed toy or to hide a tablet, and keep one dog-safe jar so it never becomes a decision made in a hurry.
• Gum and mints usually get to dogs via handbags, rucksacks, coat pockets, bedside tables and car door pockets rather than the kitchen. Hang bags up, and ask visitors, children and dog walkers to do the same.
• Human toothpaste, mouthwash, chewable vitamins, gummy supplements and some liquid or melt-in-the-mouth medicines can all contain it. Keep them shut away and never use human toothpaste on a dog.

Common questions