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My senior cat with kidney disease ate some wilted, cooked spinach that was left out overnight — is this dangerous?

Cats · Food safety

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

Short answer

The wilting itself isn't toxic, but it raises concerns about bacterial growth. For any cat, spinach in small amounts is fine, but large quantities over time can be hard on the kidneys due to oxalates. For a senior cat with known kidney disease, even a small amount of spoiled food could trigger an upset stomach or worsen their condition. Watch for signs like vomiting, diarrhoea, or decreased appetite over the next 24 hours. It's wise to call your vet to update them, as they know your cat's specific health history.

Spinach — Food safety facts

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

Small amounts are fine; large amounts of oxalates can be hard on the kidneys over time.

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

Spinach 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

A heavy salt load drives up thirst and urination, and in the worst cases leads to sodium ion poisoning, which is a genuine emergency.

Spinach can stay on the rotation, but only as an extra mouthful: 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 Spinach food facts page.

Open the full food page: Spinach food facts →