🟢 Safe
Oxalate <25 mg/serving
🟡 Caution
Oxalate 25-99 mg/serving
🔴 Avoid
Oxalate ≥100 mg/serving
🟡

Milk Thistle, Seed Powder

🟡 Caution — Moderate
90 mg oxalate / serving
Serving: 1 tsp (5 g) | Per 100 g: 1802 mg
✓ Medically Reviewed Content reviewed by OxalateWatch Editorial Team. Based on Harvard T.H. Chan SPH oxalate data (2024) and NKF/AUA dietary guidelines.

📊 Nutrition at a Glance

90 mg
Oxalate / serving
Moderate
Sodium / 100g
Pending
Protein / 100g
Pending
Calcium / 100g
Pending

📏 Oxalate by Serving Size

ServingWeightOxalateVerdict
1 tsp5 g90 mg Caution
2 x 1 tsp10 g180 mg Avoid
½ x 1 tsp2 g45 mg Caution

🏷️ Tags

Vegetables Moderate Oxalate 🟡 Oxalate Caution Calcium-Rich

🟡 See all Vegetables rated Caution for kidney stones →

⚖️ Compare this food: · vs Lettuce · vs Zucchini

🔗 Related Foods

❓ Frequently Asked Questions

Is Milk Thistle safe for kidney stones?

Proceed, but with awareness. Milk Thistle delivers 90 mg oxalate per 1 tsp. That's moderate — above the safe line, below the danger line. Portion size is your friend here.

How much oxalate is in Milk Thistle?

Here are the numbers: 90 mg oxalate in one 1 tsp of Milk Thistle (5g). Per 100 grams, that's 1802 mg. Harvard T.H. Chan SPH did the lab work (2024) — these aren't database guesses.

Is Milk Thistle a high-oxalate food?

Moderate. Milk Thistle has 90 mg oxalate per 1 tsp — not high enough to panic, not low enough to ignore. Portions matter with this one.

What are the best low-oxalate alternatives to Milk Thistle?

There are almost always safer swaps in the same food family. For Milk Thistle, check the related foods section below — the green-marked ones are your best bets. All verified by Harvard (2024).

How much Milk Thistle is safe to eat?

A standard serving (1 tsp) of Milk Thistle gives you 90 mg oxalate. Half that = 45 mg. That's the difference between a caution-level and a safe-level meal. Portions matter a lot here.

How reliable is the data for Milk Thistle?

The oxalate number for Milk Thistle — 90 mg per serving — is from Harvard's 2024 lab analysis. That part is solid. The USDA nutrition data (sodium, protein, calcium) is still being matched — we'll update when it's available.

🔍 Explore More About This Food

📚 Data Sources

Oxalate: Harvard T.H. Chan School of Public Health (2024) via OHF.

📖 Key Scientific References

Taylor EN, Curhan GC. Oxalate intake and the risk for nephrolithiasis. J Am Soc Nephrol. 2007;18(7):2198-2204. PMID: 17538185
Borghi L, Schianchi T, Meschi T, et al. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. N Engl J Med. 2002;346(2):77-84. DOI: 10.1056/NEJMoa010369
Fink HA, Akornor JW, Garimella PS, et al. Diet, fluid, or supplements for secondary prevention of nephrolithiasis. Eur Urol. 2009;56(1):72-80. DOI: 10.1016/j.eururo.2009.03.031
Ferraro PM, Taylor EN, Gambaro G, Curhan GC. Dietary and lifestyle factors for primary prevention of nephrolithiasis. BMC Nephrol. 2020;21(1):267. PMID: 32652950
Pearle MS, Goldfarb DS, Assimos DG, et al. Medical management of kidney stones: AUA guideline. J Urol. 2014;192(2):316-324. DOI: 10.1016/j.juro.2014.05.006
Liebman M, Costa G. Effects of calcium and magnesium on urinary oxalate excretion after oxalate loads. J Urol. 2000;163(5):1565-1569. PMID: 10751889
Holmes RP, Assimos DG. The impact of dietary oxalate on kidney stone formation. Urol Res. 2004;32(5):311-316. DOI: 10.1007/s00240-004-0437-3
Lin BB, Lin ME, Huang RH, et al. Dietary treatment and fluid intake for prevention of recurrent calcium stones. PLoS One. 2021;16(4):e0250257. PMID: 33872340
This is dietary reference information, NOT medical advice. Talk to your doctor or a registered dietitian before changing your diet. Oxalate tolerance varies by person, stone type, and medication.