Updated 2026-08-07 · Source: ASPCA Animal Poison Control — People Foods to Avoid Feeding Your Pets; Merck Veterinary Manual · Free · No sign-up
No — walnuts should not be given to cats. If yours has already eaten some, call your vet.
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
Don't feed
Severity
3 / 5 — Risky — more than a taste can cause real illness.
Safe amount
None
Category
Nuts
Source
ASPCA Animal Poison Control — People Foods to Avoid Feeding Your Pets; Merck Veterinary Manual · reviewed 2026-08-07 · confidence: high
Why
Same reasoning for cats: fat, size, and the mold risk on fallen or stored nuts.
Signs to watch for if your cat has eaten walnuts
Vomiting
Diarrhea or loose stools
Loss of appetite
Belly discomfort or unusual tiredness
Signs can lag by a day or more, so no symptoms does not mean your cat is clear — call rather than watch.
What to do now
Don't feed it. If your cat has already eaten some, call your vet or poison control with the amount and the timing and follow their advice.
Never induce vomiting and never give any medicine unless a vet tells you to — it can do more damage than the poison. What we will and won't tell you.
Safer alternatives for cats
A small piece of plain cooked chicken or turkey
Plain cooked fish, boneless and unseasoned
A vet-approved commercial cat treat, kept to under a tenth of daily calories
Cat grass grown indoors instead of houseplants
Fresh water — a fountain tempts many cats to drink more
This page is a reference, not veterinary advice or a diagnosis. Verdicts are transcribed from the cited source, never inferred, and a finding in one species is never copied onto the other. How we source and decide a verdict.
No — walnuts should not be given to cats. If yours has already eaten some, call your vet. Same reasoning for cats: fat, size, and the mold risk on fallen or stored nuts.
What happens if a cat eats walnuts?
Watch for: Vomiting; Diarrhea or loose stools; Loss of appetite; Belly discomfort or unusual tiredness. Some signs lag by a day — call, don't wait.
How many walnuts are dangerous for a cat?
More than a taste can cause real illness, and the risk rises with the amount and with a smaller pet. The safe amount is none — if your cat has had more, call your vet.