Why
Spinach has vitamins and iron but is high in oxalates. Oxalates bind calcium and can contribute to calcium oxalate stones, so dogs and cats with a history of stones or kidney disease should avoid it. A small amount now and then is fine for healthy pets. Korean seasoned spinach (sigeumchi-namul) is dressed with garlic, sesame oil and salt and shouldn't be shared.
How to give it / if eaten
Blanch it plain, chop it finely and give about a teaspoon to cats and small dogs or a tablespoon to large dogs, only occasionally. Blanching reduces some of the oxalates. Don't give it to pets on a stone-prevention diet.
Watch for these signs
Too much may cause vomiting or diarrhea. In pets prone to stones, watch for frequent or straining urination and blood in the urine.
FAQ
My pet ate some seasoned spinach.
Seasoned spinach usually contains garlic and salt. A chopstick-pinch is usually fine, but call your vet if your pet is small, a cat, or ate a lot.
My cat has had stones. Is even a little spinach bad?
With a history of calcium oxalate stones, it's safest to avoid spinach. While managing stones, check any treats with your vet.
General information only. Weight, age and health conditions change how a pet reacts, so ask your vet if you are worried.