Is Tomatoes Safe for Kidney Stones? (Safe)
mg oxalate
per serving
Serving: 1/2 cup (121 g)
Verdict: 🟢 Safe
Per 100g: 9 mg
Data: Harvard T.H. Chan SPH (2024)
In practical terms, Tomatoes is a low-risk food for kidney stone patients. Its 11 mg oxalate per serving stays under the 25 mg line, so it can appear in your regular rotation without extra calculation. As always, staying hydrated and getting dietary calcium supports stone prevention.
Among vegetables, Tomatoes sits well below the category average of 27 mg. For context, 219 out of 271 vegetables (80%) are rated 🟢 Safe (under 25 mg oxalate/serving). The average vegetables in our database has 27 mg oxalate per serving — which means Tomatoes is 60% below the category norm. Within its specific category, Tomatoes ranks among the lower-oxalate options. This context matters because two 'Safe' foods can have very different oxalate levels — one might have 5 mg while another has 24 mg. Both are Safe, but the first gives you more dietary flexibility. Browse all vegetables rated Safe to compare within the same verdict level.
Why does the safe threshold matter?
The 25 mg cutoff comes from clinical guidance for stone formers. Below it, a food's oxalate contribution is small enough not to move the needle for most patients. Harvard's 2024 lab data sits behind these figures — direct measurements, not estimates. For context, Tomatoes measures 11 mg per 1/2 cup, rated Safe.
Can I eat this food every day?
For Safe foods (under 25 mg/serving), daily use is generally fine. Caution and Avoid foods work better as occasional items — rotate them with safer options so no single high-oxalate food becomes a habit. Tomatoes comes in at 11 mg oxalate per 1/2 cup (Safe) in the measured database.
Where does the oxalate data come from?
Every oxalate figure is sourced from Harvard T.H. Chan SPH (2024), distributed via the OHF database. The values come from actual lab measurements of the foods — not from database averages or estimates. For Tomatoes, the measured oxalate value is 11 mg per 1/2 cup (Safe).
Should I also check sodium and calcium?
Yes — oxalate alone doesn't decide stone risk. Sodium pushes more calcium into urine, and calcium from food (not supplements) helps bind oxalate during digestion. The main food page covers sodium and calcium alongside oxalate. For context, Tomatoes measures 11 mg per 1/2 cup, rated Safe.