Other Ingredients

Xylitol

Also known as: Birch sugar, Wood sugar alcohol, E967

The tooth-friendly sugar alcohol — proven cavity prevention in gum and mints, and fatally toxic to dogs.

By IngredientWiki Editorial Team
Fact-checked by IngredientWiki Editorial Team
Updated 2026-09-26
3 min read

In short

Xylitol is a sugar alcohol found naturally in birch trees, fruits, and vegetables, now manufactured for use in sugar-free gum, mints, toothpaste, and baking. Its standout credential is dental: unlike sugar, xylitol cannot be fermented by Streptococcus mutans — the cavity-causing bacterium — and decades of trials show regular xylitol gum or lozenges reduce cavities and plaque, which is why dental organizations endorse it. It has a low glycemic impact and the usual sugar-alcohol digestive profile. One warning belongs in every xylitol household: even small amounts are rapidly fatal to dogs.

Streptococcus mutans cannot ferment xylitol — starves cavity bacteria
Clinical trials: xylitol gum/mints reduce caries
Glycemic index ~7 — very low blood-sugar impact
Highly toxic to dogs — treat like poison in dog households

What is Xylitol?

Xylitol occupies the rare sweetener niche where health claims are not just permitted but earned: it is the active ingredient in the dental aisle, not just the bakery aisle. The chemistry is a case of bacterial indigestion — mouth bacteria consume it but cannot metabolize it, wasting energy and failing to produce the acid that dissolves enamel; regular exposure measurably reduces cavity rates in trials. For humans, the caveats are minor (digestive tolerance, like all sugar alcohols). For one species, they are fatal: xylitol triggers catastrophic insulin release in dogs, and every xylitol-owning dog household needs to treat it as poison.

Where it comes from

Natural sources

Occurs naturally in birch bark, plums, strawberries, and corn fiber
The body produces small endogenous amounts
Commercially manufactured from plant xylan (birch or corn)

How it's made

Manufactured sugar alcohol sold as granulated sweetener, gum/mint ingredient, and toothpaste additive.

What it does in products

Benefits

Cavity prevention

strong evidence

Randomized trials and meta-analyses show xylitol gum and lozenges (typically 5–10 g/day) reduce caries incidence and S. mutans levels — a genuinely evidence-backed dental intervention.

Low blood-sugar impact

strong evidence

With a glycemic index around 7 (vs 65 for sucrose), xylitol produces a minimal glucose and insulin response.

Ear infection prevention

moderate evidence

Some trials in children found xylitol gum reduced recurrent acute otitis media; results are mixed across studies.

Side effects & safety

Gas, bloating, and diarrhea (common)Dose-dependent — most people tolerate up to ~40 g/day in divided amounts.

Cooling mouthfeel (common)Cosmetic — the endothermic dissolution, which also suits minty products.

Safety considerations

Considered safe in pregnancy at typical dietary intakes.
None in humans of note.
Not for: Dog households without strict separation (pet toxicity)
Not for: Irritable bowel sensitive to polyols

How it's used

In supplements

Dental benefit: 5–10 g per day, ideally divided across chewing-gum exposures after meals. Baking: substitutes 1:1 for sugar. Build tolerance gradually — bowel adaptation takes a week or two.

Regulatory status

Approved food additive and GRAS sweetener; FDA permits a qualified health claim that xylitol does not promote dental caries.
GRAS (generally recognized as safe) for food use.

Why xylitol is poison to dogs

In humans, xylitol's insulin effect is negligible; in dogs, it is explosive. Xylitol triggers a massive insulin release in canines within minutes, crashing blood sugar into life-threatening hypoglycemia — and at higher doses, acute liver failure. As little as 0.1 g/kg can cause hypoglycemia; a couple of sticks of gum can kill a small dog. The practical rules for dog households: store xylitol products (gum, mints, baking sweeteners, some peanut butters!) where dogs cannot reach them, check peanut-butter labels, and treat any suspected ingestion as a veterinary emergency — induced vomiting and dextrose support have narrow time windows. No human side effect of xylitol comes close to this severity.

Frequently asked questions

How much xylitol per day is effective for teeth?

Dental studies used about 5–10 g daily, ideally as gum or lozenges spaced through the day after meals. Frequency matters — it is the repeated exposure that suppresses cavity bacteria.

Does xylitol affect blood sugar?

Minimally — its glycemic index is about 7, versus 65 for table sugar, with a small insulin response. It is one of the most diabetic-friendly bulk sweeteners.

Which peanut butters contain xylitol?

A handful of brands use xylitol in 'reduced sugar' peanut butters (and some chewing gums, toothpastes, and protein bars). Always check the label if you have a dog — the risk profile is that serious.

The bottom line

Xylitol is the rare sweetener with a real health claim: proven cavity prevention at 5–10 g daily, minimal glycemic impact, and full baking versatility. The non-negotiable caveat is canine toxicity — in dog households, it is stored like medicine, which is to say, out of reach.

References

Xylitol and dental caries (meta-analysis). PubMed (National Library of Medicine). https://pubmed.ncbi.nlm.nih.gov/?term=xylitol+dental+caries+meta-analysis
Xylitol and Streptococcus mutans — literature search. PubMed (National Library of Medicine). https://pubmed.ncbi.nlm.nih.gov/?term=xylitol+streptococcus+mutans
Xylitol toxicity in dogs. PubMed (National Library of Medicine). https://pubmed.ncbi.nlm.nih.gov/?term=xylitol+toxicosis+dog
Xylitol compound summary. PubChem (National Library of Medicine). https://pubchem.ncbi.nlm.nih.gov/compound/6912