Updated 2026-08-07 · Source: ASPCA Animal Poison Control — People Foods to Avoid Feeding Your Pets · Free · No sign-up
Not toxic, but be careful — mayonnaise isn't poisonous to cats, and it comes with caveats that matter.
If your cat may have eaten something harmful — or any part of a lily — call your vet or the ASPCA Animal Poison Control Center at (888) 426-4435 right now — don't wait for symptoms. A consultation fee may apply to the ASPCA hotline.
Verdict for cats
Caution
Severity
2 / 5 — Mild — usually stomach upset; watch them.
Safe amount
A taste at most
Category
Human snacks
Source
ASPCA Animal Poison Control — People Foods to Avoid Feeding Your Pets · reviewed 2026-08-07 · confidence: medium
Why
Pure fat with no benefit, and garlic versions are toxic. Not for cats.
Signs to watch for if your cat has eaten mayonnaise
Repeated vomiting
A painful, tense belly — some dogs stretch into a 'praying' position
Loss of appetite and lethargy
Diarrhea
Signs vary with the amount and with the individual pet, and some appear only after a day or more. Their absence does not mean your cat is in the clear — call rather than watch.
What to do now
Don't make it a habit. Watch for vomiting, diarrhea or a lost appetite over the next day and call your vet if it doesn't settle or your cat seems unwell.
Never induce vomiting and never give any medicine unless a vet tells you to. With some substances it causes more damage than the poison. This page tells you when to get help — it never tells you how to treat at home.
Safer treats made for cats
If you're sharing food because you want to treat them, a treat formulated for cats does the job without the guesswork.
Verdicts are transcribed from the cited veterinary sources, never inferred. Where a source establishes a finding for one species only, the other species is left null and the page says to ask your vet — a dog finding is never copied onto a cat.
This page is a reference, not veterinary advice or a diagnosis. CanMyPetEat is a reference, not veterinary advice or a diagnosis. It tells you when to get help — never how to treat at home. Never induce vomiting or give any medicine unless a vet tells you to. Individual pets vary and toxicity guidance changes; your vet and the ASPCA Animal Poison Control Center are the authority.
Not toxic, but be careful — mayonnaise isn't poisonous to cats, and it comes with caveats that matter. Pure fat with no benefit, and garlic versions are toxic. Not for cats.
What happens if a cat eats mayonnaise?
Watch for: Repeated vomiting; A painful, tense belly — some dogs stretch into a 'praying' position; Loss of appetite and lethargy; Diarrhea. Signs can take hours or, for some poisons, a day or more to appear, so call your vet rather than waiting to see.
How much mayonnaise is dangerous for a cat?
The safe amount is a taste at most, as an occasional treat rather than a daily habit. Large amounts mainly cause stomach upset; if that doesn't settle within a day, call your vet.