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.