Prevention differs by stone type, and for two of the five common types the substance in the name is not the thing driving it. Uric acid stones are usually a urine pH problem rather than a uric acid problem. Calcium stones are not caused by eating calcium. If you do not know what yours was made of, that is the question worth answering before any other advice means much.
Calcium oxalate
The most commonly reported type in most published series.
What drives it is a combination: urinary calcium, urinary oxalate, urine volume, and how much citrate is present to inhibit crystal growth. Roughly half of urinary oxalate comes from diet; the rest your body makes.
The persistent misconception is that eating calcium causes it. A 2026 systematic review found the opposite pattern — a diet with normal to high calcium, alongside low protein and low sodium, was among the approaches that may reduce recurrence.
→ Calcium and kidney stones · Spinach and oxalate
Calcium phosphate
Less common, and it behaves differently enough that advice for calcium oxalate can misfire.
The key difference is urine pH. Calcium phosphate forms more readily in alkaline urine. That creates a real tension with citrate therapy, which is standard for calcium stones: citrate raises urinary citrate and lowers urinary calcium, both helpful, while the alkali load that comes with it pushes pH in an unhelpful direction. A 2019 review of citrate therapy in this stone type concludes the net clinical effect remains to be determined.
So "drink lemon water for your calcium stones" is advice whose value depends on which calcium stone you form.
Uric acid — the one most often misunderstood
Almost everyone assumes uric acid stones mean too much uric acid. Usually they do not.
Two reviews describe the same picture: uric acid stones typically occur in people with low urine pH and a normal concentration of urinary uric acid. The primary defect is excessively acidic urine rather than overproduction of urate.
Risk is higher in people with a history of gout, and in those with obesity, diabetes, or metabolic syndrome.
That inversion matters practically. If the problem is pH rather than urate, then the intervention that follows is a different one — and it is a prescription decision, not a dietary one you can work out yourself.
Struvite — infection stones
These form in the presence of particular urinary infections rather than from diet, and they can grow large. They are managed differently from every type above, and generally by a specialist.
The 2026 systematic review found that acetohydroxamic acid may reduce stone growth in adults with infection-related stones, but that evidence on preventing recurrence was insufficient and it probably increases adverse events — the only harm in that review rated moderate rather than low strength of evidence.
Cystine
Uncommon, caused by an inherited disorder of amino acid transport. It typically appears younger and recurs persistently. It is specialist territory and nothing on a general education site substitutes for that.
Drug-induced stones
Worth knowing exists: a 2018 review puts drug-induced calculi at roughly 1–2% of all renal stones. Some medicines are poorly soluble and crystallise in urine; others change urine chemistry enough to promote stones indirectly.
If you form stones and take regular medication, it is a reasonable thing to raise rather than assume is unrelated.
Why "which type" is harder to answer than it sounds
Composition is established by sending an actual stone for laboratory analysis. If you passed one or had one removed and were never told the result, ask — it may exist in your records.
Two honest caveats. Published distributions of stone types vary by region and over time — studies from different countries report meaningfully different frequencies, so a percentage you read somewhere may not describe your population. And a 2024 analysis of 24-hour urinary chemistries notes that risk from urinary factors is not a clean threshold effect: earlier work often assumed either a straight line or an arbitrary cut-off, and the real hierarchy of effects is less settled than reference ranges imply.
What to do with this
One question, at your next appointment: was my stone sent for analysis, and what did it show?
Everything else on this site — and most of what you will read elsewhere — is more useful after you can answer it.
→ How to get a 24-hour urine test · What the 2026 evidence review found