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My cat snatched a sugar-free marshmallow from a holiday dessert tray — what hidden danger should I worry about?

Cats · Food safety

Last reviewed: 2026-09-05 · Reference ranges: ASPCA, Pet Poison Helpline & Merck Veterinary Manual

Short answer

The immediate hidden danger is xylitol, an artificial sweetener common in sugar-free marshmallows that is highly toxic to pets. Even a small amount can cause a rapid drop in blood sugar and liver damage. Watch your cat closely for vomiting, lethargy, stumbling, or seizures over the next few hours. Contact your veterinarian right away if you see any of these signs or if you're unsure about the ingredients.

Marshmallow — Food safety facts

Feed with care · Cats · full breakdown on the linked food page

Sugar and gelatin, and a choking shape. Sugar-free marshmallows contain xylitol.

Dogs and cats carry the same rating (Feed with care), so the notes below hold for either pet.

Marshmallow is not poisonous to cats, but it is easy to over-feed. Rich fat, salt or seasoning can bring on vomiting or diarrhoea within a day, and repeated large portions are a recognised trigger for pancreatitis.

If it ate some before you noticed, watch for vomiting, diarrhoea, loss of appetite, unusual tiredness or a painful, swollen abdomen over the next 24 hours. A one-off small amount in a healthy adult usually passes with water and rest; repeated exposure, a puppy or kitten, a senior, or a pet with an ongoing illness is a reason to call your vet the same day.

Why these cautions matter

Even a gram or two of xylitol can trigger a sharp drop in a dog's blood sugar, and larger exposures go on to damage the liver.

Added sugar brings empty calories, and over months that means weight gain and dental disease — both far harder to undo than to avoid.

The full verdict, portion guidance and serving notes are collected on the Marshmallow food facts page.

Open the full food page: Marshmallow food facts →