Why?
Spinach contains vitamins A, B, C, and K, iron, and antioxidants. However, it is also very high in oxalic acid which can block calcium absorption and damage kidneys over time.
How much can dogs have?
A very small amount occasionally — treat it as a garnish not a regular food.
What to watch out for
Not recommended for dogs with kidney disease. The high oxalic acid content can contribute to kidney stones with regular feeding. Healthy dogs can have small amounts occasionally.