Updated 2026-08-07 · Source: VCA Animal Hospitals — pet health library · Free · No sign-up
Not toxic, but be careful — brussels sprouts aren't poisonous to cats, and they come 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
Vegetable
Source
VCA Animal Hospitals — pet health library · reviewed 2026-08-07 · confidence: medium
Why
Not toxic, no benefit, very gassy. Not worth offering to a cat.
Signs to watch for if your cat has eaten brussels sprouts
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 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 — it can do more damage than the poison. What we will and won't tell you.
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.
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.
Not toxic, but be careful — brussels sprouts aren't poisonous to cats, and they come with caveats that matter. Not toxic, no benefit, very gassy. Not worth offering to a cat.
What happens if a cat eats brussels sprouts?
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 brussels sprouts are 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.