Leafy greens

Is spinach high in oxalate?

Lower-oxalate swap: Kale, grade A, about <1 mg per 1 cup raw.

Spinach is high in oxalate: about 316 mg per 1 cup raw, which is 632% of the 50 mg a day many stone clinics aim for, or 316% of the 100 mg others allow.

If your doctor has put you on a low-oxalate diet, eat it with something high in calcium, like milk, yogurt or cheese. Calcium in the same meal binds oxalate in the gut, so less of it reaches your urine. How much calcium, and what if you don't eat dairy.

50 or 100 mg a day: which target is yours

Boiling and draining lowers oxalate, because the soluble part leaches into the water. Compare the raw and boiled rows below.

Why sources disagree on spinach

Raw spinach runs from 330 to 1,370 mg per 100 g across the 5 studies here, from 1982 to 2023, and every one of them puts a cup over a 50 mg day. Boiling cut it about in half in both studies that tested it (978 to 477, and 330 to 155 mg per 100 g), but a cooked serving packs more leaves, so cooked spinach is still very high.

Where this number comes from

Each row is one published measurement, converted to a 30 g serving (1 cup raw). The grade and the range use the rows prepared the way the serving is eaten, and take the middle. How the grades work.

* The study measured soluble oxalate only, which understates the total, so it's shown but doesn't set the grade.

By Oliver Silen · Data checked November 2, 2026 · Not medical advice