Does tea cause kidney stones, or is it being blamed for a risk it does not fully deserve? Kidney stones form when minerals in urine become concentrated, and tea often raises concern because it contains oxalate and caffeine.

Warnings about black tea or iced tea lead many people to assume that drinking tea increases the risk of developing kidney stones, especially calcium oxalate stones, the most common type. Research shows the answer is more nuanced and depends on how tea fits into hydration, diet, and personal history.

Understanding what studies actually show helps clarify when tea intake is a factor and when it can still be part of a kidney-friendly lifestyle.

Tea does not directly cause kidney stones for most people, but it often becomes a focus of concern because of its widespread consumption. Kidney stones form when minerals in urine crystallize, and tea enters the discussion mainly due to oxalate content and strong black tea consumption habits.

Many people search “does tea cause kidney stones” after hearing advice to avoid iced tea or caffeine. When tea consumption is viewed alongside hydration, diet, and other factors tied to individual circumstances, the picture becomes clearer and less alarming.

This information supports education and awareness and does not replace individual medical guidance.

Tea can influence kidney stone risk in different ways depending on type, intake level, and individual health factors. Oxalate, caffeine, and drinking habits all play a role. Understanding these details explains why tea affects people differently.

Oxalate is a natural compound found in many foods and beverages, including tea. Black tea and green tea contain more oxalate than many herbal teas.

In some people, oxalate from foods and drinks can increase oxalate levels in urine, which may raise kidney stone risk. Most people process dietary oxalate without forming stones, but sensitivity varies based on genetics and medical conditions.

Caffeine increases urine output and can change how minerals move through the body. For some people, this helps dilute urine and lower stone formation risk. For others, caffeine may increase mineral loss, which, in turn, affects kidney stone risk differently.

Tea also contains plant compounds called polyphenols that are being studied for kidney health. These compounds are not treatments, but they remain an area of ongoing research.

Calcium in food can bind to oxalate in the digestive tract, which reduces how much oxalate reaches the kidneys. Calcium-rich foods like milk, yogurt, or fortified plant milk can help balance oxalate intake when consumed with meals.

Some studies suggest black tea with milk may lower oxalate absorption compared with tea alone. This shows how eating patterns influence kidney stone risk without requiring specific changes for everyone.

Research on tea and kidney stones includes both short-term controlled trials and long-term population studies, and the findings point to a nuanced relationship. Tea does not appear to raise kidney stone risk in healthy adults under typical conditions, but individual history and metabolism still matter.

Short-term clinical research suggests that drinking 1.5 liters of black tea per day did not significantly increase 24-hour urinary oxalate levels or markers associated with kidney stone formation in healthy adults. In a controlled study published in Nutrients in 2021, researchers found that black tea consumption increased urinary citrate, a natural inhibitor of calcium oxalate stone formation, while measures of calcium oxalate, uric acid, and struvite supersaturation were stable.

It is important to note that this study included a small group of healthy men and lasted only ten days. The findings do not apply to people with kidney stone disease, recurrent kidney stones, or conditions linked to increased intestinal oxalate absorption, and further research is needed in those populations.

Large population studies generally show that tea consumption is associated with a lower likelihood of kidney stones in healthy adults. A systematic review published in Urologia Internationalis evaluated data from multiple large prospective studies and found that most reported a reduced risk of stone formation among people who regularly consumed tea, including green and black tea, as well as coffee.

The authors noted that caffeine has a mild diuretic effect and can increase urinary calcium excretion, but when fluid losses are replaced, and overall intake remains moderate, this does not appear to raise stone risk. These findings represent associations rather than direct cause and effect, and the review highlights that hydration, diet, and lifestyle patterns likely influence outcomes alongside beverage choice. The authors also emphasized variability between studies and the need for more standardized research before drawing firm conclusions for all populations.

Some people need to be careful with tea because dietary oxalate can affect kidney stone risk differently in individuals with a history of calcium oxalate stones or elevated urinary oxalate. A 2020 comprehensive review published in Nutrients explained that kidney stone risk is shaped by multiple dietary and environmental factors, and oxalate intake becomes more relevant in people who already have conditions that increase oxalate absorption or excretion.

The review noted that oxalate is widely present in plant-based foods, including tea, and that black tea generally contains more oxalate than green or herbal teas. At the same time, only about half of the daily urinary oxalate comes from food, with the remainder produced through normal metabolism. In people without intestinal malabsorption, oxalate absorption is usually limited, but it may increase when calcium intake is low or when large amounts of high-oxalate foods are consumed.

For individuals with recurrent kidney stones, kidney disease, or medical conditions that affect oxalate handling, tea intake should be considered within the context of overall diet and personal history. Reviewing tea habits with a healthcare professional can help determine an appropriate amount and type without unnecessary restriction.

Tea types differ in oxalate content, caffeine levels, and how easily people tend to overconsume them, so choosing the right kind and amount can help manage kidney stone risk without cutting tea out completely.

Moderate tea intake, often a few cups per day, has been linked with a lower likelihood of kidney stones in large population studies. There is no single daily amount that fits everyone, since caffeine sensitivity, total fluid intake, and personal circumstances vary.

Women, people with a family history of stones, or those with recurrent kidney stones may benefit from discussing tea habits and overall beverage intake with a healthcare professional.

Tea fits best into kidney health when daily habits support hydration and balanced nutrition. Kidney stone risk reflects long-term patterns, not single choices.

Drinking plenty of fluids helps prevent kidney stones by reducing dehydration. Balanced calcium intake from foods, reasonable animal protein intake, and limiting salty foods support a healthy lifestyle.

Reducing excess sodium, red meat, and alcohol also helps lower stone formation risk. Tea is only one part of daily nutrition.

Drinking plenty of fluids helps prevent kidney stones by reducing dehydration. Balanced calcium intake from foods, reasonable animal protein intake, and limiting salty foods support a healthy lifestyle.

Reducing excess sodium, red meat, and alcohol also helps lower stone formation risk. Tea is only one part of daily nutrition.

Drinking tea with meals that contain calcium can help balance oxalate absorption. Foods like milk, yogurt, fortified plant milk, broccoli, or Brussels sprouts offer useful pairing options.

Individual needs vary, and some people may require more personalized nutrition guidance.

It may be helpful to talk with a healthcare professional about tea and kidney health in certain situations, especially when personal history or symptoms are present.

• You have a history of kidney stones, including calcium oxalate stones or recurrent kidney stones

• You notice ongoing symptoms such as flank pain, changes in urine, or frequent stone formation

• You have kidney disease or other medical conditions that affect how the kidneys handle fluids and minerals

• You have questions about diet, daily fluid intake, or how tea consumption fits into a plan to prevent kidney stones

• You are using or considering kidney health or uric acid support supplements, and want to review them with a clinician who knows your medical history

Research does not show that moderate tea intake automatically causes kidney stones for most people, and large studies even link tea consumption with a lower likelihood in many cases. Tea type, total fluid intake, diet, and personal history all shape kidney stone risk.

For many people, tea can remain part of a kidney-friendly lifestyle when hydration stays adequate, added sugar is limited, and choices are guided by individual circumstances and professional advice.

The information provided in this article is for educational and informational purposes only and should not be considered a substitute for professional medical advice, diagnosis, or treatment. Please consult with your healthcare provider before starting any new dietary supplement, especially if you are pregnant, nursing, have a medical condition, or are taking other medications. Never disregard professional medical advice or delay in seeking it because of something you have read in this article.

1. Barghouthy, Y., Corrales, M., Doizi, S., Somani, B. K., & Traxer, O. (2021). Tea and coffee consumption and the risk of urinary stones-a systematic review of the epidemiological data. World journal of urology, 39(8), 2895–2901. https://doi.org/10.1007/s00345-020-03561-w

2. Ferraro, P. M., Bargagli, M., Trinchieri, A., & Gambaro, G. (2020). Risk of Kidney Stones: Influence of Dietary Factors, Dietary Patterns, and Vegetarian-Vegan Diets. Nutrients, 12(3), 779. https://doi.org/10.3390/nu12030779

3. Massey, L. K., & Whiting, S. J. (1993). Caffeine, urinary calcium, calcium metabolism and bone. The Journal of nutrition, 123(9), 1611–1614. https://doi.org/10.1093/jn/123.9.1611

4. Mitchell, T., Kumar, P., Reddy, T., Wood, K. D., Knight, J., Assimos, D. G., & Holmes, R. P. (2019). Dietary oxalate and kidney stone formation. American journal of physiology. Renal physiology, 316(3), F409–F413. https://doi.org/10.1152/ajprenal.00373.2018

5. Savage, G. P., Charrier, M. J., & Vanhanen, L. (2003). Bioavailability of soluble oxalate from tea and the effect of consuming milk with the tea. European journal of clinical nutrition, 57(3), 415–419. https://doi.org/10.1038/sj.ejcn.1601572

6. Siener, R., & Hesse, A. (2021). Effect of Black Tea Consumption on Urinary Risk Factors for Kidney Stone Formation. Nutrients, 13(12), 4434. https://doi.org/10.3390/nu13124434