Swollen legs by end of day, bloated stomach, tight rings: water retention drives the search for a natural diuretic, preferably a powerful one. Plants are no shortage of, from horsetail to dandelion, and their reputation is often long-standing. What's more often lacking are measurements in humans.
This guide ranks natural diuretics based on what studies have actually measured: urine volume, sodium elimination, 24-hour water balance. It includes plants, but also less expected and better-supported levers, like salt, potassium and water itself, what coffee really does, what the scale loses when water is eliminated, and situations where caution is warranted.
The best supported are not plants: reducing salt, which lowered extracellular water by one liter in four weeks in kidney patients; drinking, since one liter of water produces 1.2 to 1.3 kg of urine in four hours; and potassium, which increases sodium elimination in two hours. Among plants, horsetail has the best human trial, with an effect comparable to 25 mg of hydrochlorothiazide, a pharmaceutical diuretic. Dandelion leaf and cherry stems have modest effects; hibiscus increases sodium elimination and lowers blood pressure.
What lacks evidence : dandelion root performed no better than water, orthosiphon did not increase urine volume in the only human trial, and nettle, parsley and birch have only animal data. Coffee causes slight urination at rest in non-drinkers, not in regular users. No diuretic causes fat loss: the scale loses water. Caution with lithium, with blood pressure medications containing potassium, in case of kidney disease, allergy to Asteraceae or kidney stones.
- Diuretic, draining, water retention: what are we talking about
- The ranking: what has a measured effect in humans
- Horsetail, the most studied plant diuretic
- Dandelion, cherry stems, hibiscus: more modest effects
- Orthosiphon, nettle, parsley, birch: what's missing
- Salt, potassium, water, coffee: everyday levers
- Natural diuretic for weight loss: what the scale loses
- Precautions and interactions
- The water retention plan
- Frequently asked questions
Diuretic, draining, water retention: what are we talking about
A diuretic increases urine volume. A natriuretic increases sodium elimination by the kidneys; since sodium retains water, water follows. The two don't always go together: in the horsetail trial, urine production increased without sodium elimination changing. The word draining, for its part, has no definition in studies: in practice it refers to plants reputed to promote water elimination.
Water retention, finally, is an excess of water in the tissues, which causes swollen legs and ankles, a tense belly or puffy fingers. It often follows salt, heat, prolonged standing or sitting and the menstrual cycle; it can also signal heart, kidney, liver or vein disease. Our article to find out if you have water retention details the signs.
The ranking: what has a measured effect in humans
| Natural diuretic | Measured effect in humans | Level of evidence |
|---|---|---|
| Less salt | One liter of extracellular water and 2.3 kg less in 4 weeks, in kidney patients | Strong |
| Water | One liter consumed produces 1.2 to 1.3 kg of urine in 4 hours | Strong |
| Potassium | Increased sodium elimination 2 hours after 40 mmol, in healthy adults | Moderate |
| Horsetail | Negative water balance of 322 mL over 24 hours, comparable to a pharmaceutical diuretic | Moderate, one double-blind trial |
| Hibiscus infusion | Sodium elimination, lower blood pressure | Moderate for blood pressure |
| Dandelion leaf | More frequent urination within 5 hours | Weak, without placebo |
| Cherry stems | Slight increase in urine volume | Weak, 13 volunteers |
| Caffeine | 109 mL additional urine at rest; nothing in regular drinkers | Solid, weak effect |
| Dandelion root | No better than water alone over 4 hours | Negative trial |
| Orthosiphon, corn silk, plantain | No effect on urine volume at 12 and 24 hours | Negative trial, outdated |
| Nettle, parsley, birch | No human measurements found | Animal data |
This ranking is based on evidence in humans, not on reputation. It mainly shows that the most effective ways to combat water retention are found on your plate and in your glass, and that a plant, even well-chosen, plays only a supporting role.
Horsetail, the most well-studied plant diuretic
Thirty-six healthy men each received, in turn, 900 mg per day of dry extract of field horsetail, 25 mg of hydrochlorothiazide, a medication diuretic, or placebo, for four days. Over 24 hours, the water balance was negative by 322 mL with horsetail and 232 mL with hydrochlorothiazide, versus a positive balance of 130 mL with placebo: horsetail performed significantly better than placebo and no worse than the medication. Sodium and potassium elimination did not change, and blood tests remained normal.
Carneiro DM, Freire RC, Honório TC, et al. Evid Based Complement Alternat Med 2014;2014:760683. DOI: 10.1155/2014/760683
It is the only plant diuretic to have been compared to a medication in a controlled trial in humans. Its limitations are clear: men only, four days of treatment, large variations from person to person. Tolerance beyond four days was not studied in this trial, and horsetail was not tested in combination with a medication diuretic: under diuretic treatment, it should not be added without medical advice.
Dandelion, cherry stems, hibiscus: more modest effects
Seventeen volunteers took a hydroalcoholic extract of fresh dandelion leaves, 8 mL three times during the day, while recording their fluid intake and urination. Urination frequency increased within five hours of the first dose, and the ratio of urine passed to fluid consumed within five hours of the second dose; the third dose changed nothing. The study had no placebo group.
Clare BA, Conroy RS, Spelman K. J Altern Complement Med 2009;15(8):929-934. DOI: 10.1089/acm.2008.0152
The plant part matters. In 2026, a crossover trial in 14 active young adults compared one liter of water alone and one liter of water with approximately 2.1 g of dandelion root powder: 1,164 g of urine in four hours with water alone, 1,268 g with dandelion, a non-significant difference. The positive data thus concern the leaf.
Cherry stems, the quintessential home remedy, were tested as powder, at 2 g, in 13 volunteers: urine volume slightly increased, as did the elimination of sodium, chloride and calcium, without adverse effects. The increase in urinary calcium prompts the authors to exercise caution in people prone to kidney stones. Our article on cherry stems details their uses.
Thehibiscus, finally, acts mainly on blood pressure. In 75 hypertensive patients, an infusion of 10 g of calyces each morning for four weeks reduced blood pressure from 139 to 124 mmHg for systolic and from 91 to 80 for diastolic, with no difference compared to captopril, a blood pressure medication, and a natriuretic effect was observed. A meta-analysis of 17 trials published in 2022 found a reduction in systolic pressure of 7.1 mmHg compared to placebo. Under blood pressure treatment, this effect is additive: it should be discussed with your doctor.
Orthosiphon, nettle, parsley, birch: what's missing
Theorthosiphon, or Java tea, is widely used in Asia and Europe. In rats, its extract increases urine volume proportionally to the dose, less than furosemide and hydrochlorothiazide. The only human trial found, conducted in Vietnam in 1992 in a double-blind placebo-controlled design, tested four traditional remedies, including orthosiphon, corn silk, and plantain: none increased urine volume or sodium elimination over 12 and 24 hours. The doses are not specified in the study abstract, and orthosiphon is used today mainly in combination.
Fornettle, the parsley and the birch, the data are from animal studies. An extract of nettle infused in rats increased diuresis and sodium elimination; an extract of parsley seeds increased urine volume in rats by inhibiting a renal sodium pump; an extract of birch leaves modified neither urine volume nor sodium in rats. No measurements in humans were found for these three plants, nor for celery or asparagus, often cited among diuretic vegetables.
Not having been measured in humans does not mean not acting: these plants have a long traditional use and sometimes effects in animals. It means that we know neither the magnitude of their effect in humans, nor the dose that produces it. They therefore reserve themselves a supporting role, behind better-established levers.
Salt, potassium, water, coffee: everyday tools
Fifty-eight patients with chronic kidney disease stage 3 or 4 followed for four weeks a diet with less than 2 g of sodium per day, or about 5 g of salt, then their usual diet, or vice versa. With less salt, extracellular water volume decreased by 1.02 L, weight by 2.3 kg, and 24-hour systolic blood pressure by 10.8 mmHg.
Saran R, Padilla RL, Gillespie BW, et al. Clin J Am Soc Nephrol 2017;12(3):399-407. DOI: 10.2215/CJN.01120216
Salt. Sodium retains water: reducing its intake is the most direct natural diuretic. The trial above focused on kidney patients; in the general adult population, the DASH-sodium trial showed that progressive salt reduction lowers blood pressure in stages. Salt comes mainly from bread, prepared dishes, processed meats, cheeses, and sauces.
Potassium. In a randomized trial published in 2026, a single dose of 40 mmol of potassium, as chloride or citrate, increased urinary sodium elimination within two hours in healthy adults, but not in patients with kidney disease, whose blood potassium increased more. A meta-analysis of 22 trials published in the BMJ associates increased potassium intake with lower blood pressure in hypertensive patients, with no adverse effect on the kidneys when they function normally. Fruits, vegetables, and legumes are the best sources; our article on foods that lower blood pressure provides a list.
Water. Drinking makes you urinate: one liter of water consumed in thirty minutes produces 1.2 to 1.3 kg of urine within four hours. Restricting beverages does not reduce water retention; thirst remains the best guide, with more water in hot weather.
Coffee and tea. A meta-analysis of 16 studies shows that approximately 300 mg of caffeine, two to three coffees, add 109 mL of urine on average, at rest but not during exercise, with a more pronounced effect in women. At least 250 to 300 mg is required in someone who does not consume it, and habit creates tolerance: in 50 regular coffee drinkers, four cups a day for three days hydrated as much as water, with 2,409 mL of urine over 24 hours versus 2,428 mL. In the beverage hydration index trial, coffee and tea did not produce more urine than water.
Magnesium. In 38 women, 200 mg of magnesium per day reduced premenstrual symptoms of water retention, weight gain, bloating, breast tenderness, and bloating, starting from the second cycle of use.
Natural diuretic for weight loss: what the scale loses
Eight runners took 40 mg of furosemide, a potent diuretic drug, before races of 1,500 m, 5 km, and 10 km. They lost 1.6 to 2.1% of their body weight and 9.9 to 12.3% of their blood plasma volume, and ran more slowly: 1.31 minutes slower over 5 km, 2.62 minutes slower over 10 km.
Armstrong LE, Costill DL, Fink WJ. Med Sci Sports Exerc 1985;17(4):456-461. DOI: 10.1249/00005768-198508000-00009
Even a potent prescription diuretic only causes a loss of a few percent of body weight, and this weight is water, partially drawn from the blood. No study found shows fat loss under diuretics, natural or otherwise. A diuretic can deflate and lighten a silhouette that retains water; it does not replace a caloric deficit. Our guide how many calories per day to lose weight provides the method.
Precautions and Interactions
| Situation | Risk | Source |
|---|---|---|
| Lithium | Diuretics disrupt its elimination; one case of toxicity with herbal diuretics | Case from 2001, review from 2016 |
| ACE inhibitors, sartans, spironolactone, amiloride, with potassium | Hyperkalemia, sometimes severe | Case from 2011 |
| Chronic kidney disease | Potassium poorly eliminated, without effect on sodium | Trial from 2026 |
| Prescription diuretic | Possible additive effect of horsetail, not studied | Trial from 2014 |
| Allergy to wormwood or Asteraceae | Cross-reactions with dandelion | Study from 2007 |
| Kidney stones | Cherry stems: increased urinary calcium | Study from 2009 |
| Treated hypertension | Hibiscus: blood pressure reduction that adds to treatment | Trial from 2004 |
| Endurance exercise | Dehydration and decreased performance | Trial from 1985 |
Lithium deserves special mention: it is a medication with a narrow margin between effective and toxic doses, and diuretics are among the medications involved in its toxicity. A case published in 2001 describes lithium poisoning associated with herbal diuretics. For dandelion, a study in 6,497 patients with respiratory allergies found sensitization to dandelion pollen in 8.5% of them, with cross-reactions with wormwood and chrysanthemum.
Two patients experienced cardiac arrest, from which they recovered, following significant potassium intake from a salt substitute and a sports supplement. The authors note that severe hyperkalemia of dietary origin is exceptional with normal kidneys, and occurs mainly in cases of renal insufficiency or treatment with potassium-sparing diuretics, ACE inhibitors, or sartans. In these situations, any potassium supplement should be discussed with a doctor.
The water retention plan
For the legs, other measures matter, such as walking and elevating the legs in the evening: our guide to natural remedies for heavy legs details them, and the one on water retention reviews twelve plants and nutrients.
Potassium citrate, magnesium bisglycinate, dandelion, orthosiphon and cherry stems, in three capsules per day: 285 mg of potassium and 120 mg of magnesium, combined with three traditional drainage plants. As a complement to a lower-salt diet rich in fruits and vegetables. If taking lithium, diuretics, blood pressure medication or if you have kidney disease, consult your doctor.
View DiuretineOur article on lymphatic drainage covers massages and techniques.
Frequently asked questions
What is the most powerful natural diuretic?
Among plants, horsetail has the best human data: 900 mg per day of dry extract resulted in a negative water balance of 322 mL over 24 hours, compared to a positive balance of 130 mL under placebo, an effect comparable to 25 mg of hydrochlorothiazide. This is a single trial, in 36 men, over 4 days. Reducing salt and increasing potassium remain the best-established strategies.
Which diuretic plants have proven effective?
Horsetail, with a positive double-blind trial. Dandelion leaf and cherry stems have modest effects in small studies, and hibiscus increases sodium elimination while lowering blood pressure. Dandelion root and orthosiphon did not increase urine volume in humans; nettle, parsley and birch have only animal data.
Which vegetables are diuretic?
No human studies measure diuresis after celery, asparagus, or parsley. Fruits and vegetables work primarily through their potassium, which helps the kidneys eliminate sodium and the water it retains: 40 mmol of potassium increased sodium elimination within 2 hours in healthy adults. Their water content also plays a role.
Do diuretic herbal teas work?
Their primary effect is that of water: 1 liter consumed in 30 minutes produces 1.2 to 1.3 kg of urine in 4 hours, and tea does not increase urination more than water does. Hibiscus infusion, 10 g of calyces each morning, additionally lowered blood pressure with a natriuretic effect. For other herbal infusions, human data are lacking.
Is coffee diuretic?
Somewhat, especially at rest and in those who don't drink it regularly: approximately 300 mg of caffeine adds about 109 mL of urine on average. In regular coffee drinkers, four cups per day hydrate as much as water does: 2,409 mL of urine over 24 hours versus 2,428 mL with water. Coffee therefore counts toward daily fluid intake.
Does a natural diuretic cause weight loss?
No, it causes water loss, not fat loss. Even a pharmaceutical diuretic, furosemide, caused only 1.6 to 2.1% weight loss, with 10 to 12% less blood volume and slower exercise performance. This weight returns as soon as you drink fluids. No study shows fat loss under diuretic use.
What should you take for water retention?
First, less salt: at under 2 g of sodium per day for 4 weeks, extracellular water volume decreased by 1 liter in kidney patients. Then potassium, through fruits, vegetables, and legumes. Magnesium, 200 mg per day, reduced premenstrual water retention symptoms by the second cycle. A plant like horsetail can provide additional support.
Cherry stems, dandelion: do grandma's remedies work?
Modestly. Cherry stems, 2 g in powder form, slightly increased urine volume in 13 volunteers. Dandelion leaf extract increased urination frequency within 5 hours, whereas dandelion root powder performed no better than water alone over 4 hours.
Diuretic or draining: what's the difference?
A diuretic increases urine volume; a natriuretic increases sodium elimination, which carries water with it, such as potassium or hibiscus do. Horsetail increased diuresis without changing sodium elimination. Draining has no definition in studies: the term practically designates plants reputed to promote water elimination.
Who should avoid natural diuretics?
People on lithium, whose elimination is disrupted by diuretics; on ACE inhibitors, sartans, spironolactone, or amiloride with potassium intake due to hyperkalemia risk; people with kidney disease or heart failure; those allergic to Asteraceae for dandelion; and people prone to kidney stones for cherry stems. Medical consultation is essential in these situations.
Sources
The studies cited below were identified via PubMed.
- Carneiro DM, Freire RC, Honório TC, et al. Double-blind randomized trial of the acute diuretic effect of Equisetum arvense (field horsetail) in healthy volunteers. Evidence-Based Complementary and Alternative Medicine, 2014;2014:760683. DOI
- Clare BA, Conroy RS, Spelman K. Diuretic effect in humans of a Taraxacum officinale leaf extract over one day. Journal of Alternative and Complementary Medicine, 2009;15(8):929-934. DOI
- Gavin J, Caulfield C, Egan B. Dandelion root powder adds no diuretic effect over 4 hours to water alone in young active adults. International Journal of Sport Nutrition and Exercise Metabolism, 2026;36(5):523-531. DOI
- Hooman N, Mojab F, Nickavar B, Pouryousefi-Kermani P. Diuretic effect of cherry stem powder in healthy volunteers. Pakistan Journal of Pharmaceutical Sciences, 2009;22(4):381-383. PubMed
- Herrera-Arellano A, Flores-Romero S, Chávez-Soto MA, Tortoriello J. Efficacy and tolerability of a standardized Hibiscus sabdariffa extract in mild to moderate hypertension: randomized controlled trial. Phytomedicine, 2004;11(5):375-382. DOI
- Ellis LR, et al. Systematic review and meta-analysis of the effects of Hibiscus sabdariffa on blood pressure and cardiometabolic markers. Nutrition Reviews, 2022;80(6):1723-1737. DOI
- Doan DD, Nguyen NH, Doan HK, et al. Individual and combined diuretic effects of four traditional Vietnamese remedies: corn silk, Imperata cylindrica, plantain, and orthosiphon. Journal of Ethnopharmacology, 1992;36(3):225-231. DOI
- Adam Y, et al. Diuretic properties of Orthosiphon stamineus Benth. Journal of Ethnopharmacology, 2009;124(1):154-158. DOI
- Kreydiyyeh SI, Usta J. Diuretic effect and mechanism of action of parsley. Journal of Ethnopharmacology, 2002;79(3):353-357. DOI
- Tahri A, et al. Acute diuretic, natriuretic, and hypotensive effects of an aqueous extract infusion of Urtica dioica in rats. Journal of Ethnopharmacology, 2000;73(1-2):95-100. DOI
- Peron G, et al. Metabolic effects of Betula alba leaf extract in rats using urinary metabolomics. Metabolites, 2025;15(7):471. DOI
- Saran R, Padilla RL, Gillespie BW, et al. Randomized crossover trial of dietary sodium restriction in stage 3 and 4 chronic kidney disease. Clinical Journal of the American Society of Nephrology, 2017;12(3):399-407. DOI
- Sacks FM, et al. Effects on blood pressure of a reduction in dietary sodium and the DASH diet. New England Journal of Medicine, 2001;344(1):3-10. DOI
- Wouda RD, Karsten M, Michels EHA, et al. Natriuretic response to acute oral potassium loading in healthy subjects and patients with chronic kidney disease: a randomized trial. Nephrology Dialysis Transplantation, 2026;41(2):255-264. DOI
- Aburto NJ, et al. Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses. BMJ, 2013;346:f1378. DOI
- Maughan RJ, Watson P, Cordery PA, et al. Randomized trial of the effect of different beverages on hydration: a beverage hydration index. American Journal of Clinical Nutrition, 2016;103(3):717-723. DOI
- Zhang Y, Coca A, Casa DJ, Antonio J, Green JM, Bishop PA. Caffeine and diuresis at rest and during exercise: meta-analysis. Journal of Science and Medicine in Sport, 2015;18(5):569-574. DOI
- Maughan RJ, Griffin J. Caffeine and fluid balance: review. Journal of Human Nutrition and Dietetics, 2003;16(6):411-420. DOI
- Killer SC, Blannin AK, Jeukendrup AE. No dehydration with moderate coffee consumption: crossover trial in real-life conditions. PLoS One, 2014;9(1):e84154. DOI
- Walker AF, De Souza MC, Vickers MF, et al. Magnesium relieves premenstrual symptoms of water retention. Journal of Women's Health, 1998;7(9):1157-1165. DOI
- Armstrong LE, Costill DL, Fink WJ. Effect of diuretic-induced dehydration on running performance. Medicine and Science in Sports and Exercise, 1985;17(4):456-461. DOI
- Pyevich D, Bogenschutz MP. Herbal diuretics and lithium toxicity. American Journal of Psychiatry, 2001;158(8):1329. DOI
- Finley PR. Lithium drug interactions: update. Clinical Pharmacokinetics, 2016;55(8):925-941. DOI
- John SK, Rangan Y, Block CA, Koff MD. Life-threatening hyperkalemia after dietary supplements: rare or underrecognized? American Journal of Emergency Medicine, 2011;29(9):1237.e1-2. DOI
- Lee YW, Choi SY, Lee EK, et al. Cross-reactivity between Asteraceae pollens: mugwort, chrysanthemum and dandelion. Annals of Allergy, Asthma and Immunology, 2007;99(6):526-533. DOI
