on September 02, 2026
Urinary calculosis, or nephrolithiasis when the stone forms in the kidney, is a condition characterized by the precipitation and aggregation of substances normally present in the urine. Stone formation does not depend simply on the presence of calcium, oxalate, or uric acid, but on the dynamic relationship between substances that promote crystallization and factors that hinder it.
Stone composition analysis, when available, is one of the most important tools for developing a personalized prevention strategy. Similarly, metabolic analysis of the urine can provide information on urine volume, calcium, oxalate, citrate, uric acid, sodium, pH, and other parameters involved in stone risk.
The goal of prevention is not to indiscriminately eliminate all minerals from the diet, but to reduce the urinary supersaturation of lithogenic compounds and, when necessary, increase the natural factors that hinder the nucleation, growth, and aggregation of crystals.
The main international guidelines on calculosis emphasize that prevention must be tailored to the stone composition and the individual's metabolic profile. (uroweb.org)
How a urinary stone forms
Stone formation is a complex physicochemical and biological process.
Urine normally contains numerous dissolved salts. When their concentration exceeds a certain threshold, supersaturation may occur.
Supersaturation is a necessary, but not always sufficient, condition for stone formation. Nucleation, crystal growth, and aggregation processes must also occur.
An initial crystal can serve as a nucleus for the aggregation of other molecules. The persistence of crystals in the urinary tract and their ability to adhere to epithelial surfaces further contribute to their growth.
The main types of urinary stones include:
- calcium oxalate stones;
- calcium phosphate stones;
- uric acid stones;
- struvite stones;
- cystine stones.
Calcium stones, particularly those composed of calcium oxalate, are the most common type.
Urinary pH is particularly important for some types of stones. A persistently acidic urinary environment can promote the precipitation of uric acid, while different conditions can favor other types of crystallization.
The simple definition of “renal calculosis” is therefore not sufficient to establish truly effective prevention.
The importance of water and urine volume
Hydration is one of the most important pillars of stone prevention.
Increasing fluid intake promotes the production of a greater urine volume and reduces the concentration of lithogenic substances.
The most important result is not simply “drinking a lot” on a few occasions during the day, but distributing fluid intake to maintain adequate diuresis.
European and American guidelines generally recommend a urine volume of at least 2–2.5 liters per day in individuals with a history of calculosis, unless there are specific clinical contraindications. To achieve this goal, fluid intake must be adapted to individual losses, ambient temperature, physical activity, and health conditions. (uroweb.org)
A randomized prospective study has shown that increasing fluid intake to increase urine volume can significantly reduce the risk of recurrence of idiopathic calcium calculosis. Borghi and colleagues observed that maintaining a high urine volume was associated with a lower probability of recurrence compared to a group without specific hydration intervention. (pubmed.ncbi.nlm.nih.gov)
Hydration should be considered with particular attention in individuals exposed to high temperatures, intense work activities, prolonged sports activity, or profuse sweating.
Dietary sodium and urinary calcium excretion
Excess sodium is one of the most relevant dietary factors in calcium calculosis.
Increased sodium intake can promote increased urinary calcium excretion. This phenomenon is particularly important in individuals predisposed to hypercalciuria.
Reducing salt does not mean eliminating sodium entirely, but avoiding excessive consumption of added salt and sodium-rich processed foods.
Cold cuts, snacks, industrial baked goods, very salty cheeses, sauces, and numerous ready-made foods can contribute significantly to the overall sodium load.
Reducing dietary sodium is often an integral part of the prevention strategy in patients with calcium calculosis and hypercalciuria.
Animal proteins and lithogenic risk
Very high consumption of animal proteins can affect several urinary factors involved in stone formation.
Diets characterized by a high animal protein load can increase urinary calcium and uric acid excretion and alter urinary pH, with a possible reduction in urinary citrate.
Citrate is one of the main natural inhibitors of calcium crystallization in the urine. Its ability to bind calcium can help reduce the availability of the mineral for crystal formation.
Moderating animal protein intake is therefore generally preferable to high-protein diets, especially in individuals with specific metabolic alterations.
A clinical study published in the New England Journal of Medicine compared a diet with normal calcium content but reduced animal protein and salt with a low-calcium diet in men with recurrent calcium oxalate calculosis and hypercalciuria. After five years, the normocalcemic diet combined with reduced sodium and animal protein proved more effective than the low-calcium diet in preventing recurrences. (pubmed.ncbi.nlm.nih.gov)
This result has helped change one of the most widespread traditional beliefs in stone prevention: simply reducing dietary calcium is not necessarily a protective strategy.
Dietary calcium should not be eliminated
In individuals with calcium calculosis, it may seem intuitive to drastically reduce calcium in the diet. In reality, for many people, this strategy can be counterproductive.
Calcium present in foods can bind to oxalate in the intestinal tract. The formed complex can be eliminated with the feces, reducing the amount of oxalate available for intestinal absorption and subsequent urinary excretion.
A diet too low in calcium can therefore increase oxalate absorption and, in some individuals, increase oxaluria.
For this reason, in people with calcium oxalate calculosis, a normal intake of calcium through food is generally recommended, unless otherwise indicated clinically.
The situation with calcium supplements, however, requires a more individualized assessment. The relationship between calcium supplementation and stone risk depends on the dose, the method of intake, the timing relative to meals, and the individual metabolic profile.
It is therefore incorrect to state that every calcium supplement automatically increases the risk of stones. However, in predisposed individuals, supplementation should be evaluated by a physician and incorporated into a metabolic monitoring context.
Oxalate: when it is necessary to reduce it
Oxalate is present in numerous plant-based foods. Some foods, such as spinach, rhubarb, and certain other plant sources, can contain particularly high amounts.
Indiscriminate restriction of all foods containing oxalate is generally not necessary for all patients with calculosis.
The strategy must be personalized based on the stone type and the results of the metabolic analysis.
In individuals with hyperoxaluria, greater attention may be advised regarding foods particularly rich in oxalate and the correct pairing with dietary sources of calcium during meals.
Intestinal health can significantly affect oxalate metabolism. Some conditions associated with intestinal fat malabsorption can increase oxalate absorption and promote so-called enteric hyperoxaluria.
Fruit, vegetables, and citrate
Fruit and vegetables can contribute to stone prevention through several mechanisms.
They are sources of potassium, water, and organic compounds that can contribute to a favorable urinary profile. A diet rich in plant-based foods can also promote an adequate intake of citrate.
Citrate is one of the most important inhibitors of calcium stone formation. Its presence in the urine can reduce the formation of insoluble complexes by binding to calcium.
In some patients with hypocitraturia, pharmacological intervention with potassium citrate may be necessary, according to medical prescription.
Citrus fruits can be an interesting source of citrate, but their use does not replace pharmacological therapy when indicated.
The main predisposing factors
Urinary calculosis is influenced by genetic, metabolic, environmental, and behavioral factors.
Factors that can increase risk include family history, male sex in certain age groups, reduced urine volume, exposure to high temperatures, and certain dietary habits.
Dehydration is a particularly important factor in people who work in hot environments, engage in intense sports activity, or are exposed to high ambient temperatures.
The geographical distribution of calculosis also shows differences related to climate, dietary habits, and water availability.
The so-called “stone belt,” observed in some regions of the United States, represents an example of the interaction between environmental conditions and stone risk.
The Mediterranean area also has climatic conditions that can promote greater fluid loss during warm periods.
Why knowing the stone composition is fundamental
Stone prevention must be personalized.
A uric acid stone requires different strategies than a calcium oxalate stone. Similarly, calculosis associated with cystinuria or urinary tract infections requires a specific assessment.
Stone analysis allows the identification of the predominant substance, while a 24-hour urine collection enables the assessment of the main metabolic alterations.
The most frequently considered parameters include:
- urine volume;
- calcium;
- oxalate;
- citrate;
- uric acid;
- sodium;
- pH;
- creatinine;
- other parameters selected based on the clinical picture.
A personalized approach is particularly important in patients with frequent recurrences.
Herbal medicine in urinary tract stones
Medicinal plants traditionally used to promote diuresis and urinary tract health have long been of interest.
So-called “dilution therapy” represents one of the most widely used traditional concepts in urological herbal medicine. Increasing urine volume can help dilute substances present in the urine and promote the flushing of the urinary tract.
However, it is important to emphasize that a plant with diuretic activity does not automatically dissolve a stone.
The most plausible role of many medicinal plants traditionally used for kidney stones is to support increased diuresis and, in some cases, to interact with inflammatory processes or specific crystallization mechanisms.
Clinical evidence for many species remains limited and does not allow them to replace validated preventive strategies.
Grass-of-Parnassus (Elymus repens or Agropyron repens)
Grass-of-Parnassus is traditionally used in herbal medicine to promote diuresis and as support for irritative conditions of the urinary tract.
The rhizome contains polysaccharides, phenolic compounds, and other constituents.
European herbal tradition has associated this plant with increased urinary flow and the “flushing” of the urinary tract.
However, modern specific clinical evidence on stone prevention remains limited.
For this reason, it is more accurate to consider Grass-of-Parnassus as a plant traditionally used to promote diuresis, rather than as a proven treatment for dissolving or eliminating stones.
As with other diuretic plants, its use should be carefully evaluated in cases of heart or kidney failure and in individuals taking diuretic medications.
Nettle-rack (Ononis spinosa)
Nettle-rack root is one of the herbal drugs traditionally used to promote diuresis.
European tradition recognizes its use in the treatment of minor urinary tract conditions and to increase urinary flow.
Its possible benefit in kidney stones can be interpreted primarily in terms of increasing urine volume and flushing the urinary tract.
However, there is insufficient clinical evidence to state that nettle-rack prevents all types of kidney stones.
Its use should be avoided when an increase in fluid intake is contraindicated, such as in some cases of heart or kidney failure.
Solidago (Solidago virgaurea)
Goldenrod is one of the best-known plants in European herbal medicine for urinary tract health.
The aerial parts contain flavonoids, triterpene saponins, and phenolic compounds.
Tradition attributes diuretic properties to the plant and the ability to promote the flushing of the urinary tract.
The European HMPC monograph recognizes a traditional use of Solidago to increase urine output and promote the flushing of the urinary tract in minor conditions. (ema.europa.eu)
However, it is not correct to turn this traditional indication into clinical evidence of stone dissolution.
Its use should be accompanied by adequate fluid intake and requires caution in individuals in whom increased diuresis may be contraindicated.
Alder (Fraxinus excelsior)
Alder leaves are traditionally used in herbal medicine for various applications.
The phytocomplex includes iridoids, flavonoids, and other compounds.
Some traditional uses have involved support for diuresis and the elimination of metabolites.
However, specific clinical evidence regarding the prevention or treatment of urinary tract stones is insufficient.
Alder should therefore not be considered a proven uricolytic agent in humans without specific clinical studies on the preparation used.
Corn silk (Zea mays)
Corn silk is traditionally used to promote diuresis and urinary tract health.
Its action can be interpreted primarily as support for increasing urine volume.
Tradition has also prescribed its use in the presence of kidney stones and urinary tract irritation.
However, there is no robust clinical evidence demonstrating the ability of corn silk to dissolve kidney stones.
Its use should therefore be considered complementary and not a substitute for a urological evaluation.
Nettle (Urtica dioica)
Nettle is a plant used in herbal medicine for various indications.
The root is studied primarily in the context of lower urinary tract symptoms associated with benign prostatic hyperplasia, while other parts of the plant are traditionally used to promote diuresis.
Increased diuresis may represent a possible mechanism to support the prevention of urinary salt precipitation, but there is insufficient evidence to consider nettle a specific therapy for kidney stones.
Lespedeza (Lespedeza capitata)
Lespedeza has traditionally been used in some herbal preparations intended to support urinary function.
Diuretic effects and changes in the elimination of nitrogenous metabolites have been described, but modern clinical evidence on the prevention of nephrolithiasis is limited.
Its eventual use should therefore be interpreted as part of herbal tradition and not as a validated treatment for kidney stones.
Cranberry (Vaccinium macrocarpon) and urinary tract health
Cranberry, or American cranberry, is particularly well known for its possible role in preventing recurrent urinary tract infections.
Type A proanthocyanidins have been studied for their ability to interfere with the adhesion of certain strains of Escherichia coli to the urothelium.
This mechanism is biologically distinct from the prevention of stones.
Research on cranberry primarily concerns recurrent urinary tract infections and does not allow it to be considered a treatment for kidney stones.
Systematic reviews have observed that specific cranberry preparations can reduce the risk of recurrent urinary tract infections in some populations, but the effects depend on the formulation and clinical context. (cochrane.org)
It is important not to confuse the prevention of urinary tract infections with the prevention of kidney stones.
Furthermore, some cranberry products can contribute significantly to oxalate intake. In individuals with specific forms of calcium oxalate kidney stones and hyperoxaluria, their use should therefore be evaluated individually.
Beta-sitosterol: what role in urological health?
Beta-sitosterol is a phytosterol naturally present in numerous plants.
Its most studied application in the urological field concerns the improvement of certain symptoms associated with benign prostatic hyperplasia.
However, beta-sitosterol does not represent a treatment for urinary tract stones.
Its eventual inclusion in a formulation intended for urinary tract health must be evaluated based on the specific objective of the product and must not be presented as a substance capable of directly preventing or dissolving stones.
Phyllanthus niruri: one of the most studied plants for kidney stones
Among the plants frequently associated with the tradition of kidney stones, Phyllanthus niruri is probably one of the most studied species.
It is known in several traditions by names that recall its possible use in the “breaking” or elimination of stones.
Experimental studies have suggested that plant extracts may influence the processes of nucleation, aggregation, and growth of calcium oxalate crystals.
Some clinical and observational studies have also explored the possible effect of Phyllanthus niruri preparations on urinary parameters and the risk of recurrence.
The available evidence is interesting, but heterogeneous and does not yet allow the plant to be considered an equivalent treatment to standard therapies for nephrolithiasis. (pubmed.ncbi.nlm.nih.gov)
Its scientific interest derives primarily from the possibility that some plant constituents may interact with crystal growth, in addition to any effects on the urinary profile.
Other traditionally used plants
Several other species have traditionally been used in preparations intended for urinary function and diuresis.
Among these are Asparagus officinalis, Betula spp., Equisetum arvense, Herniaria glabra, Polygonum aviculare, Ruscus aculeatus, Taraxacum officinale, and Tilia platyphyllos.
Their phytochemical compositions differ, and it is not scientifically correct to attribute the same activity to all of them.
In many formulations, the rationale for the combination is the integration of activities traditionally associated with increased diuresis, support of the urinary tract, and modulation of inflammatory processes.
The combination of multiple plants does not automatically determine a greater effect. Each association should also be evaluated for possible interactions, contraindications, and the characteristics of the individual components.
“Dilution therapy” and its physiological rationale
The traditional concept of dilution therapy has a simple physiological basis.
Increasing urine volume reduces the concentration of many substances present in the urine.
Greater dilution can reduce the likelihood that certain substances reach conditions favorable for supersaturation and precipitation.
However, the benefit depends primarily on the total volume of fluids introduced and the urine volume actually produced.
A diuretic herbal preparation cannot replace water. If a person increases urinary elimination without an adequate fluid intake, the result can be counterproductive.
For this reason, the fundamental principle of prevention remains the maintenance of adequate hydration.
When herbal medicine can provide support
Phytotherapeutic preparations may be considered, in selected individuals, as a possible complement to a broader preventive strategy.
Their role may be more rational when incorporated into a program that includes:
adequate hydration;
a diet tailored to the type of stone;
moderation of sodium intake;
adequate dietary calcium intake;
an assessment of animal protein intake;
monitoring of oxalate in individuals with excessive urinary excretion;
assessment of urinary citrate and pH;
regular monitoring in individuals with recurrences.
Medicinal plants should not be used with the aim of delaying medical evaluation when symptoms of renal colic, fever, blood in the urine, or a significant reduction in urine output are present.
Renal colic, infection, and obstruction: when to seek medical attention
Urinary tract stones may be asymptomatic, but they can also cause severe pain, nausea, vomiting, and blood in the urine.
Renal colic associated with fever or chills may represent a clinically urgent situation, especially when there is an obstruction of the urinary tract associated with infection.
A marked reduction in urine output, persistent uncontrollable pain, or deterioration of general condition also require medical evaluation.
Phytotherapy and supplements should not be used to delay the treatment of a possible urinary obstruction.
Prevention must be personalized
Urinary tract stones are not a single disease, but a group of conditions characterized by the formation of different types of crystals.
For this reason, effective prevention requires knowing as much as possible about the individual profile.
Stone analysis, when available, and metabolic urine studies are essential tools for identifying the predominant factors.
Adequate hydration is the most universally applicable preventive measure. Sodium reduction, moderation of animal proteins, and maintenance of adequate calcium intake through food represent further important elements, especially in calcium stones.
Oxalate restriction should be reserved especially for situations in which there is a real metabolic indication.
Phytotherapy may offer interesting support to promote diuresis and the well-being of the urinary tract, but the available evidence varies widely among the different species.
Some plants, such as Phyllanthus niruri, deserve further study for their possible effects on crystallization processes. Other species belong predominantly to the European phytotherapeutic tradition of flushing the urinary tract.
The most effective strategy therefore remains that which integrates knowledge of stone composition, metabolic evaluation, personalized nutrition, adequate hydration, and, when necessary, pharmacological or urological treatment.
Note: the information in this article is for informational and educational purposes only and does not represent medical advice. Urinary tract stones require a personalized clinical evaluation. In the presence of severe pain, fever, chills, persistent vomiting, blood in the urine, reduced urine output, or suspected urinary obstruction, it is necessary to seek medical attention promptly. Medicinal plants and supplements may provide complementary support, but they do not replace diagnosis, pharmacological therapy, or urological treatment.
Essential scientific bibliography
Borghi L, Meschi T, Amato F, Briganti A, Novarini A, Giannini A. Urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. Journal of Urology. 1996;155(3):839-843. (pubmed.ncbi.nlm.nih.gov)
Borghi L, Schianchi T, Meschi T, et al. Comparison of two diets for the prevention of recurrent stones in idiopathic hypercalciuria. New England Journal of Medicine. 2002;346(2):77-84. (pubmed.ncbi.nlm.nih.gov)
European Association of Urology. EAU Guidelines on Urolithiasis. Update available in the European guidelines on metabolic evaluation and recurrence prevention. (uroweb.org)
European Association of Urology. EAU Guidelines on Urolithiasis. (uroweb.org)
Fink HA, Wilt TJ, Eidman KE, et al. Medical management to prevent recurrent nephrolithiasis in adults: a systematic review for an American College of Physicians Clinical Guideline. Annals of Internal Medicine. 2013;158(7):535-543.
European Medicines Agency, HMPC. Solidaginis herba – herbal medicinal product. Monograph on the traditional use of Solidago to promote increased urinary flow and flushing of the urinary tract. (ema.europa.eu)
Fu Z, Liska D, Talan D, Chung M. Cranberry reduces the risk of urinary tract infection recurrence in otherwise healthy women: a systematic review and meta-analysis. Subsequent studies and reviews have further evaluated the role of cranberry preparations in recurrent urinary tract infections.
Williams G, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database of Systematic Reviews. 2023 update. (cochrane.org)
