Oxalate <25 mg/serving
Oxalate 25-99 mg/serving
Oxalate ≥100 mg/serving
Watermelon might be the single best food for kidney stone patients during hot weather. 1 mg of oxalate per slice, 92% water by weight, and naturally sweet without added sugar. It's doing double duty: satisfying your sweet craving AND contributing directly to your hydration. Multiple oxalate databases — Harvard, UCI Kidney Stone Center, and USDA FoodData Central — all agree that watermelon is essentially oxalate-free. For calcium oxalate stone formers, watermelon is as safe as food gets.
📊 Nutrition at a Glance
📏 Oxalate by Serving Size
| Serving | Weight | Oxalate | Verdict |
|---|---|---|---|
| 1 slice | 280 g | 1 mg | Safe |
| 2 x 1 slice | 560 g | 2 mg | Safe |
| ½ x 1 slice | 140 g | 0.5 mg | Safe |
🏷️ Tags
🟢 See all Fruits rated Safe for kidney stones →
⚖️ Compare this food: · vs Rhubarb · vs Herbs and Spices Lemon Myrtle →
🔗 Related Foods
🟢 Safe alternatives (recommended)
⚠️ Other foods in this category to watch
❓ Frequently Asked Questions
Should I avoid Watermelon if I have kidney stones?
No red flags here. Just 1 mg per 1 slice — well below the 25 mg danger line. You can keep Watermelon in your regular rotation. Data comes from Harvard (2024).
What's the oxalate content of Watermelon?
Here are the numbers: 1 mg oxalate in one 1 slice of Watermelon (280g). Per 100 grams, that's 3 mg. Harvard T.H. Chan SPH did the lab work (2024) — these aren't database guesses.
Is Watermelon high in oxalates?
Definitely low. 1 mg oxalate per 1 slice. That's the green zone. No restrictions needed for this food.
What are the best low-oxalate alternatives to Watermelon?
There are almost always safer swaps in the same food family. For Watermelon, check the related foods section below — the green-marked ones are your best bets. All verified by Harvard (2024).
How much sodium does Watermelon have?
Low sodium: 1 mg/100g. That's a non-issue for kidney stones. Just don't undo it by drowning it in salt during cooking.