Does Coffee Cause Kidney Stones? What the Research Says
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If you have ever passed a kidney stone, you probably never want to repeat the experience, and you may have heard that coffee is to blame. So, does coffee cause kidney stones? According to the largest studies available, no clear link points that way. Several big cohort studies have found that people who drink coffee, including decaf, tend to have a somewhat lower risk of kidney stones than people who rarely drink it. That is an association, not proof that coffee prevents stones, and what you add to your coffee may matter more than the coffee itself.
Here is what the research says, how to read it, and the practical questions people ask after a stone.
Key takeaways
- A 2013 analysis of three large US cohorts found caffeinated coffee was associated with a 26% lower risk of kidney stones and decaf with a 16% lower risk.
- A 2014 study from the same cohorts linked higher caffeine intake with lower stone risk, and a later genetic (Mendelian randomization) study pointed the same way.
- Brewed coffee is generally considered low in oxalate; black tea contains more.
- Fluid intake is central to stone prevention. Sugary drinks have been associated with higher risk.
- If you have had stones, follow the plan your doctor gives you based on your stone type.
In this article
- Kidney stones in brief
- Does coffee cause kidney stones? The main studies
- Evidence at a glance
- Oxalate, caffeine and calcium: the possible mechanisms
- What you add matters
- FAQ
Kidney stones in brief
Kidney stones are hard deposits that form when minerals in urine become concentrated enough to crystallize. The most common type is calcium oxalate. Others include calcium phosphate, uric acid and less common types. Stone type matters, because diet advice differs between them.
The US National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) lists drinking enough fluid as one of the most important ways to help prevent stones, along with dietary changes tailored to the stone type.
Does coffee cause kidney stones? The main studies
The 2013 beverage study
Researchers led by Pietro Manuel Ferraro analyzed data from more than 190,000 people in three long-running US cohorts: the Health Professionals Follow-up Study and the Nurses’ Health Studies I and II. They compared how often people drank different beverages with the risk of developing kidney stones over years of follow-up.
Compared with people who drank less than one serving per week, those who drank one or more servings per day had:
- a 26% lower risk with caffeinated coffee
- a 16% lower risk with decaf coffee
- an 11% lower risk with tea
In the same analysis, sugar-sweetened colas and fruit punch were associated with a higher risk. The study appeared in the Clinical Journal of the American Society of Nephrology.
The 2014 caffeine study
A follow-up paper in the American Journal of Clinical Nutrition looked specifically at caffeine from all sources across the same three cohorts. People in the highest fifth of caffeine intake had a lower risk of stones than those in the lowest fifth, in each of the three groups.
Genetic evidence
Observational studies can be confounded: coffee drinkers may differ in many ways from non-drinkers. Mendelian randomization studies try to get around that by using gene variants linked to caffeine intake. A study reported in 2021 found that genetically predicted higher caffeine consumption was associated with a lower risk of kidney stones, which supports the observational findings, though it does not settle the question by itself.
Evidence at a glance
| Study | Design | Main finding | Limits |
|---|---|---|---|
| Ferraro et al., 2013 | Three prospective cohorts, 190,000+ adults | Daily caffeinated coffee linked to 26% lower risk; decaf 16% lower | Self-reported diet; mostly US health professionals |
| Ferraro et al., 2014 | Same cohorts, total caffeine | Highest caffeine intake linked to lower risk | Observational; cannot prove cause |
| Mendelian randomization, 2021 | Genetic variants as proxies for caffeine intake | Higher predicted caffeine linked to lower risk | Relies on assumptions about the genes used |
Taken together, the evidence does not support the idea that moderate coffee drinking causes kidney stones in the general population. The fact that decaf also showed a lower risk suggests that more than caffeine may be involved, possibly simply the extra fluid.
Oxalate, caffeine and calcium: the possible mechanisms
Is coffee high in oxalate?
Brewed coffee is generally considered a low-oxalate drink per cup. Black tea contains noticeably more. If you follow a low-oxalate diet for calcium oxalate stones, ask your dietitian how coffee fits your daily oxalate target.
Does caffeine affect calcium in urine?
Caffeine can modestly increase the amount of calcium excreted in urine, which sounds like it should raise stone risk. However, caffeine and coffee also increase urine flow, which dilutes stone-forming minerals. The large studies above suggest the net effect is not harmful, but researchers still debate the details.
Fluid is the common thread
A cup of coffee is mostly water. Despite its mild diuretic effect, coffee contributes to daily fluid intake, a point covered in our article on whether coffee dehydrates you. For people prone to stones, many doctors recommend drinking enough to produce a large volume of urine daily; your doctor can give you a personal target.
What you add matters
| Add-in | What to know |
|---|---|
| Sugar and sweet syrups | Sugar-sweetened drinks have been associated with higher stone risk; keep added sugar modest |
| Milk | Dietary calcium with meals is generally encouraged for calcium oxalate stone formers, as it binds oxalate in the gut; follow your doctor’s advice |
| Plant milks | Some, such as almond-based drinks, can contain more oxalate; check labels and ask your dietitian |
| Energy drinks or very high caffeine | Stay within the commonly cited limit of about 400 mg of caffeine a day for most healthy adults |
For context, the FDA and EFSA consider up to 400 mg of caffeine per day generally safe for most healthy adults, with single doses up to 200 mg (EFSA). Pregnant or breastfeeding people are advised to stay under 200 mg per day. Our guide on how much caffeine is too much explains these numbers.
Enjoying coffee your way
If you want to keep coffee in your routine with less caffeine or less sugar, flavor helps. Our Peru Decaf has caramel and citrus notes without the caffeine, and Half Caf blends regular coffee with water-process decaf for half the caffeine. A smooth medium roast like our Breakfast Blend is easy to drink black, so you may find you need less sugar.
Coffee and kidney stones FAQ
Can I drink coffee after passing a kidney stone?
For most people, research does not show that coffee raises risk. Your stone type and medical history matter, so ask your doctor or urologist.
Is decaf better than regular coffee for kidney stones?
In the 2013 study, both were linked to lower risk, with a slightly larger association for caffeinated coffee. Neither has been shown to prevent stones.
Is coffee or tea better for kidney stones?
Both were associated with lower risk in the cohort study. Black tea contains more oxalate than coffee, which may matter for some calcium oxalate stone formers.
Does coffee with milk cause kidney stones?
There is no evidence that milk in coffee causes stones. Dietary calcium is generally not restricted for stone formers, but follow your clinician’s advice.
Sources
- Ferraro PM, Taylor EN, Gambaro G, Curhan GC. Soda and other beverages and the risk of kidney stones. Clinical Journal of the American Society of Nephrology, 2013.
- Ferraro PM, Taylor EN, Gambaro G, Curhan GC. Caffeine intake and the risk of kidney stones. American Journal of Clinical Nutrition, 2014 (abstract via UroToday).
- Study: coffee, caffeinated products may reduce the risk of kidney stones, Healio, 2021.
- Eating, diet and nutrition for kidney stones, NIDDK, accessed 2026.
- Spilling the beans: how much caffeine is too much?, US FDA, accessed 2026.
Facts checked in October 2026.
This article is for general information only and is not medical advice. If you have a health condition, are pregnant or take medication, ask your doctor before changing your caffeine intake.
Keep reading: Caffeine myths · Is coffee acidic? · Single origins