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My 5 kg cat ate a quarter of a keto granola bar sweetened with erythritol — is that a dangerous amount for her weight?

Cats · Food safety

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

Short answer

That amount is unlikely to be dangerous, but it will probably cause an upset stomach. Erythritol is a sugar alcohol that draws water into the gut, leading to diarrhea and gas. A quarter of a bar for a 5 kg cat is enough to trigger these effects, but it's not toxic like xylitol. Watch for soft stools or diarrhea over the next day. Ensure she drinks water to stay hydrated. If the diarrhea is severe or lasts more than 48 hours, call your vet.

Erythritol — Food safety facts

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

A sugar alcohol that causes diarrhoea and gas. Do not confuse it with xylitol — that one is toxic.

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

Erythritol 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.

Erythritol can turn up now and then, but not as a daily habit: keep the rest of the day's food unchanged and watch the litter box and how quickly they finish the next meal.

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

Open the full food page: Erythritol food facts →