Xylitol is a sugar alcohol used as a sweetener in sugar-free gum, candy, baked goods, peanut butter, toothpaste, and an expanding range of consumer products. In people, it is safe. In dogs, it can cause life-threatening hypoglycemia within 30 minutes and irreversible liver failure within 12 to 24 hours.

The toxicology is well characterized, the mechanism is understood, and the treatment window is narrow. Here is what the evidence says about xylitol poisoning in dogs — including the newly important detail that xylitol is increasingly listed on ingredient labels as birch sugar, a name many pet owners do not recognize as dangerous.

Why Xylitol Is Toxic to Dogs

Dogs absorb xylitol rapidly from the gastrointestinal tract. When xylitol enters the bloodstream, it triggers a massive insulin release from the pancreas — three to seven times the normal amount, according to the Merck Veterinary Manual. This insulin surge drives blood glucose down to dangerous levels.

The mechanism is species-specific. Humans do not release significant insulin in response to xylitol. Dogs are uniquely sensitive, and the difference is not a matter of degree — it is qualitative.

At higher doses, xylitol also causes dose-dependent hepatic necrosis (liver cell death). The mechanism of liver injury is not fully understood, but the clinical pattern is consistent: dogs that ingest large amounts of xylitol can progress from hypoglycemia to acute liver failure, coagulopathy, and death, even after blood glucose has been stabilized.

Toxic doses

A single piece of some sugar-free gums contains enough xylitol to cause hypoglycemia in a small dog. A package of gum can contain enough to cause liver failure.

Where Xylitol Hides

Xylitol is found in a growing number of household products. Common sources include:

• Sugar-free gum and mints (the most frequently reported source of canine exposure)
• Sugar-free candy and baked goods
• Peanut butter and other nut butters (some "health" brands add xylitol for sweetness)
• Toothpaste and mouthwash
• Over-the-counter medications and supplements (chewable vitamins, melatonin gummies, some liquid formulations)
• Skin care products

The "birch sugar" problem

Xylitol is increasingly listed on ingredient labels as birch sugar, birch bark extract, or birch sap. This is the same compound — the alternative names come from the fact that xylitol was originally derived from birch bark. Pet owners scanning ingredient lists for "xylitol" may miss these alternate names entirely.

The name change is not required by regulation but is permitted under FDA labeling rules. Veterinary teams should specifically warn clients that birch sugar = xylitol, and that both names need to be checked.

Gabapentin and xylitol

Some human gabapentin formulations (particularly liquid solutions) contain xylitol as a sweetener. Gabapentin is widely prescribed off-label in veterinary medicine for seizure management and chronic pain. If a veterinarian is prescribing a human gabapentin product, the specific formulation should be checked to confirm it does not contain xylitol.

Clinical Signs

Signs of xylitol poisoning develop in two phases:

Phase 1: Hypoglycemia (30 minutes to 12 hours)

• Vomiting (often the first sign)
• Lethargy and weakness
• Ataxia (incoordination, stumbling)
• Tremors
• Seizures
• Collapse and coma in severe cases

Onset can be as fast as 20–30 minutes after ingestion, though some products (particularly certain sugar-free gums) are absorbed more slowly, delaying signs by up to 12–18 hours.

Phase 2: Hepatic necrosis (12–72 hours)

• Jaundice (yellowing of skin, gums, sclera)
• Worsening vomiting and diarrhea
• Decreased appetite
• Depression
• Coagulopathy (bleeding disorders)
• Elevated liver enzymes on blood work

Not every dog that becomes hypoglycemic will develop liver failure, but the risk increases with dose. Dogs that ingest ≥ 0.5 g/kg are at significant risk for hepatic injury even if hypoglycemia is managed promptly.

Diagnosis

There is no specific test for xylitol. Diagnosis is based on:

1. Known or suspected exposure — a pet owner who saw their dog eat sugar-free gum, or found an empty package
2. Clinical signs consistent with hypoglycemia and/or liver injury
3. Blood work showing low blood glucose and/or elevated liver enzymes (ALT, ALP, total bilirubin)

Blood glucose should be checked immediately in any dog with suspected xylitol ingestion. Liver enzyme values should be obtained at presentation and monitored at 12, 24, and 72 hours for higher-dose exposures.

Treatment

There is no antidote for xylitol poisoning.

Treatment is supportive and time-sensitive.

GI decontamination

• Emesis induction may be considered if the ingestion was within the past 30 minutes and the dog is still asymptomatic (no hypoglycemia signs). Because hypoglycemia can develop rapidly, emesis should only be attempted under veterinary supervision.
• Activated charcoal is not recommended. In vitro studies show that activated charcoal does not effectively bind xylitol.

Hypoglycemia management

• IV dextrose is the cornerstone of treatment. A bolus of 1–2 mL/kg of 25% dextrose IV, followed by a constant-rate infusion (CRI) of IV fluids containing 2.5–5% dextrose to maintain blood glucose.
• Hypoglycemia may persist for 24 hours or more, and gabapentin or other medications should not be administered until glucose is stable.
• Blood glucose should be monitored every 1–2 hours until stable without supplemental dextrose.

Hepatic protection

For ingestions ≥ 0.5 g/kg, even if the dog is normoglycemic:

• IV dextrose should be started prophylactically
• Hepatoprotectants should be considered, though evidence for efficacy in xylitol toxicosis specifically is limited:
  • N-acetylcysteine (NAC): 140–280 mg/kg loading dose, then 70 mg/kg IV or PO q6h
  • S-adenosylmethionine (SAMe): 17–20 mg/kg/day PO
  • Silymarin: 20–50 mg/kg/day PO
  • Vitamin E: 100–400 IU PO q12h
• Coagulation monitoring (PT/PTT) and fresh frozen plasma if coagulopathy develops

Hospitalization and monitoring

Dogs with significant xylitol ingestion should be hospitalized for a minimum of 12–24 hours, with blood glucose monitored hourly. Liver enzyme values should be rechecked at 24 and 72 hours. Dogs that develop hepatic injury may require extended hospitalization and a guarded prognosis.

Prognosis

Most dogs that receive prompt, aggressive treatment for hypoglycemia recover fully. The prognosis is more guarded for dogs that develop acute liver failure, though survival even at massive doses has been reported with aggressive supportive care. A 2016 case report documented survival in a Chihuahua that ingested 45 g/kg — approximately 100 times the hepatotoxic threshold — with intensive treatment including NAC, SAMe, fresh frozen plasma, and IV dextrose.

The key variable is time. The sooner treatment begins after ingestion, the better the outcome.

Prevention

1. Check all labels for xylitol AND birch sugar. Both names refer to the same compound.
2. Keep sugar-free products out of reach. Gum, mints, and candy in purses and coat pockets are a common access point.
3. Verify peanut butter ingredients before using it to hide medication. Some brands add xylitol.
4. Check any human medication prescribed for your dog (especially liquid formulations) with your veterinarian to confirm it does not contain xylitol.
5. Know the emergency numbers. ASPCA Animal Poison Control Center: 888-426-4435. Pet Poison Helpline: 855-764-7661.

Sources

• Merck Veterinary Manual. "Xylitol Toxicosis in Dogs." merckvetmanual.com/toxicology/food-hazards/xylitol-toxicosis-in-dogs
• FDA. "Paws Off Xylitol; It's Dangerous for Dogs." fda.gov/consumers/consumer-updates/paws-xylitol-its-dangerous-dogs
• Cornell University College of Veterinary Medicine. "Xylitol Toxicities." vet.cornell.edu/departments-centers-and-institutes/riney-canine-health-center/canine-health-topics/xylitol-toxicities
• PetMD. "Xylitol Poisoning in Dogs." Reviewed 2025. petmd.com/dog/poisoning/xylitol-poisoning-in-dogs
• Xavier FG, Kogika MM, de Sousa RS. "Acute Hepatic Failure in a Dog after Xylitol Ingestion." J Vet Emerg Crit Care. 2016;26(5): doi: 10.1111/vec.12465. PMC4880608. pmc.ncbi.nlm.nih.gov/articles/PMC4880608
• dvm360. "New Findings on the Effects of Xylitol Ingestion in Dogs." dvm360.com/view/new-findings-effects-xylitol-ingestion-dogs
• Small Door Veterinary. "Xylitol Poisoning in Dogs." smalldoorvet.com/learning-center/medical/xylitol-poisoning-dogs