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My cat ate steamed plain mustard greens two hours ago and is now vomiting — is this expected?

Cats · Food safety

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

Short answer

Vomiting two hours after eating steamed plain mustard greens is not a typical reaction, because mustard greens themselves are safe for cats when cooked and unseasoned. The vomiting may be caused by something else — a hairball, a sudden diet change, or ingestion of an herb or spice mixed into the greens. Watch for additional signs such as diarrhoea, lethargy, or refusal to eat, and keep your cat hydrated. If vomiting continues beyond a single episode or your cat seems weak, contact your vet for advice.

Mustard greens — Food safety facts

Safe to share · Cats · full breakdown on the linked food page

Steamed and plain, small amounts.

Dogs and cats carry the same rating (Safe to share), so the notes below hold for either pet.

Mustard greens is not toxic to cats. The real limit is calories, fat and salt, so treat it as a small extra alongside the normal ration rather than a meal in itself.

There is no poisoning risk here, and the usual problem is simply eating too much at once: a heavy fat or salt load can bring on loose stools or a single vomit. Offer water, keep an eye on the pet for 24 hours, and do not induce vomiting.

Why these cautions matter

Caffeine overstimulates the heart and nervous system, and pets clear it so slowly that tremors and restlessness drag on far longer than they would in a person.

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

Open the full food page: Mustard greens food facts →