“Xylitol is very dangerous for dogs." (Caption adds: "It can be in gum, candy and some sugar-free products, even some peanut butters. Always read the label before you share. If your dog ate something with xylitol, call your vet right away.")”

The toxicity is established in the dog and is recognised by the US regulator, by poison control centres and by the veterinary reference literature. The FDA states that sugarless gum may contain xylitol, a class of sweetener known as sugar alcohol, that xylitol is present in many products and foods for human use, and that it can have devastating effects on pets. FDA's Center for Veterinary Medicine reports having received multiple reports over several years of dogs poisoned by xylitol, many pertaining to chewing gum, and notes the sweetener may also be labelled as birch sugar or wood sugar. The mechanism is species-specific. The Merck Veterinary Manual states that in most mammals xylitol has no notable effect on insulin levels, but in dogs it stimulates a rapid, dose-dependent insulin release that can result in profound hypoglycemia, while the mechanism for hepatic necrosis is unclear. Merck describes the most common clinical sign as profound hypoglycemia, which may result in vomiting, weakness, lethargy, hypokalemia, seizures and coma, with some dogs developing severe liver injury of unknown mechanism. A peer-reviewed clinical review states that xylitol causes hypoglycaemia due to stimulation of insulin release and liver failure in dogs, but not in cats, rabbits or rodents. Doses are low relative to everyday products. A dose of 0.05 g/kg can cause hypoglycaemia in dogs, and more than 0.5 g/kg can cause liver failure, though the liver effect may be idiosyncratic rather than strictly dose-related. Pet Poison Helpline gives the poisoning threshold as at least 0.1 grams per kilogram of body weight and notes that chewing gums and breath mints typically contain 0.22 to 1.0 gram of xylitol per piece. Another clinical review puts the hypoglycemia risk at doses above 100 mg/kg and hepatic damage risk above 500 mg/kg, with serious signs generally not anticipated below 100 mg/kg, and stresses that the dose should be calculated when an exposure occurs. Merck's hepatotoxin chapter describes xylitol as extraordinarily toxic to dogs, with as little as 0.1 g/kg causing clinical hypoglycemia and hepatic necrosis in some dogs, while noting a breadth of individual responses. On the sources named in the post: Reporting on specialty nut butters notes that Nuts 'n More, Krush Nutrition and P-28 Foods have all made peanut butter or nut-based spreads containing xylitol. A veterinary consumer reference lists Go Nuts Co., Krush Nutrition, Nuts 'n More and P28 Foods as brands that have sold xylitol-containing peanut butter, and notes formulations can change, so a product should not be assumed safe on brand name alone. Pet Poison Helpline notes many sugarless gums and candies contain xylitol and that baked goods may also be made with it. On urgency: FDA advises that if you think your dog may have eaten a product containing xylitol, you should call your vet, emergency clinic, or animal poison control center. A drug-information summary citing FDA notes that low blood sugar and other serious effects may in some cases not appear for up to 12 to 24 hours and the dog may need hospitalisation for monitoring, and that vomiting should not be induced unless a veterinarian has directed it. Pet Poison Helpline notes signs can develop within 10 to 15 minutes of ingestion, and that rarely signs may not begin until many hours later. The ASPCA states most dogs do recover even with large xylitol ingestions, but veterinary care matters. Exposure is not rare. The ASPCA reported that in 2021 alone its Animal Poison Control Center hotline fielded more than 6,100 calls for xylitol ingestion. Pet Poison Helpline's director of veterinary medicine is quoted as saying cases remain nearly 75% higher in 2025 than in 2020, and that xylitol-related cases were the fourth most common dog poisoning call the helpline received in both 2024 and 2025.