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Nettle
Nettle — what the European monograph actually supports, what it is not for, the form and how long it is meant to be used, side effects, and the 3 medicine interactions documented for it.
This is a reference page, not a diagnosis and not a prescription. Herbal products are real pharmacology: they have effects, side effects and interactions with medicines. Tell your doctor and your pharmacist everything you take, including teas and supplements, and never stop or change a prescribed medicine because of anything you read here.
What it is
Urtica dioica L. — leaf and herb (Urticae folium), and root (Urticae radix)
Local names across the region this site serves: nõges (ET) · nokkonen (FI) · крапива (RU).
Grouped here under Joints, urinary tract and hormones. Regulatory position: EU herbal monograph — traditional use (separate monographs for leaf and root).
What the evidence supports
The registered indication: Leaf: to increase the amount of urine and so flush the urinary tract in minor complaints, and for minor joint pain. Root: lower urinary tract symptoms related to benign enlargement of the prostate.
Leaf and root are two different medicines from one plant, and mixing them up is the usual error. The leaf — the spring soup and tea plant across the whole Baltic and Nordic region — carries an aquaretic indication: increasing urine volume to flush the urinary tract, with a firm instruction to drink plenty of fluid while doing it. That flushing use is explicitly not a treatment for a urinary infection. Fever, pain in the flank, blood in the urine, or symptoms lasting more than a couple of days mean a clinician, because an untreated kidney infection is serious and a diuretic tea does nothing about the bacteria. The root has a completely separate indication for the urinary symptoms of an enlarged prostate, with the same rule attached: a doctor should have excluded other causes of those symptoms first. Nutritionally the cooked or dried leaf is a genuinely good spring green — cooking and drying destroy the sting.
C — Traditional use only Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it.
What it is not for
Urinary tract infections, kidney stones, or prostate symptoms that have never been assessed. Flushing regimes are actively wrong in heart failure and in kidney disease where fluid is restricted.
Form, strength and how long
Dried leaf as an infusion, fresh leaf as food, leaf extracts and tinctures, and separately root extracts in capsules for prostate symptoms.
Duration. Short courses for the leaf indications. Prostate symptoms are a long-term matter and belong with a doctor.
No gram figure appears on this page on purpose. The plant part, the extraction solvent and the drug-to-extract ratio together define a preparation, and a number taken from one does not describe another. The reasoning is set out on the hub; the amount that applies to you is the one printed on the pack you are holding, and a pharmacist will read it with you.
Side effects
Mild stomach upset and allergic skin reactions. The stinging hairs on the fresh plant cause the familiar rash, which is mechanical rather than allergic.
Who should avoid it
Do not use flushing regimes where fluid must be restricted — heart failure, kidney impairment. Not established in pregnancy for medicinal amounts.
Interactions with medicines
| Medicine or substance | What is described |
|---|---|
| Anticoagulants and antiplatelets (warfarin, DOACs, aspirin, clopidogrel) | Nettle leaf is high in vitamin K, the nutrient warfarin works against. A sudden switch to daily nettle soup or nettle tea in spring can shift INR. Keep intake steady and tell whoever monitors it — this is one of the few genuinely seasonal interactions in northern Europe. |
| Blood-pressure medicines, diuretics and corticosteroids | Increasing urine output alongside diuretics or blood-pressure medicines is not automatically harmful, but it belongs on the list, especially with heart failure or kidney disease, where a flushing regime is exactly the wrong idea. |
| Diabetes medicines and insulin | Reports of blood-glucose lowering exist; monitor rather than assume if you are on glucose-lowering medicines. |
The reverse view — start from the medicine rather than the plant — is in the medicine, food and alcohol interactions reference, and summarised for every herb on this site.
Sources: European Medicines Agency — Committee on Herbal Medicinal Products (HMPC), European Union herbal monographs · NIH National Center for Complementary and Integrative Health — herb fact sheets · checked 2026-09-06
Frequently asked questions
What is nettle used for?
Leaf: to increase the amount of urine and so flush the urinary tract in minor complaints, and for minor joint pain. Root: lower urinary tract symptoms related to benign enlargement of the prostate. Leaf and root are two different medicines from one plant, and mixing them up is the usual error. The leaf — the spring soup and tea plant across the whole Baltic and Nordic region — carries an aquaretic indication: increasing urine volume to flush the urinary tract, with a firm instruction to drink plenty of fluid while doing it. That flushing use is explicitly not a treatment for a urinary infection. Fever, pain in the flank, blood in the urine, or symptoms lasting more than a couple of days mean a clinician, because an untreated kidney infection is serious and a diuretic tea does nothing about the bacteria. The root has a completely separate indication for the urinary symptoms of an enlarged prostate, with the same rule attached: a doctor should have excluded other causes of those symptoms first. Nutritionally the cooked or dried leaf is a genuinely good spring green — cooking and drying destroy the sting.
Does nettle work?
Graded C here: Plausible from thirty or more years of use, which is what a traditional-use registration means. No clinical evidence was required and none has settled it. Urinary tract infections, kidney stones, or prostate symptoms that have never been assessed. Flushing regimes are actively wrong in heart failure and in kidney disease where fluid is restricted.
How much nettle should I take?
This reference does not print gram figures, because they do not transfer between preparations of different extract strength. What can be said honestly is the form and the duration: Dried leaf as an infusion, fresh leaf as food, leaf extracts and tinctures, and separately root extracts in capsules for prostate symptoms. Short courses for the leaf indications. Prostate symptoms are a long-term matter and belong with a doctor.
What are the side effects of nettle?
Mild stomach upset and allergic skin reactions. The stinging hairs on the fresh plant cause the familiar rash, which is mechanical rather than allergic.
Does nettle interact with medicines?
Yes — documented for Anticoagulants, warfarin, Blood pressure, Diabetes medicines. Each one is described on this page, with a link to the medicine-side reference where one exists.
Others in joints, urinary tract and hormones
Saw palmetto
Relief of lower urinary tract symptoms related to benign prostatic hyperplasia, after a doctor has excluded serious conditions.
Cranberry
Reducing the chance of repeat urinary tract infections in some groups — not treating an infection that is already present.
Black cohosh
Relief of menopausal complaints such as hot flushes and profuse sweating.
Devil's claw
Relief of minor joint pain, and of mild digestive complaints such as bloating and loss of appetite.
Feverfew
Prophylaxis of migraine headaches, after serious conditions have been excluded by a doctor.
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