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Limited evidenceGeneral health

Yellow Dock

A bitter root traditionally used as a gentle laxative and a tonic for iron. It contains anthraquinones that plausibly explain the laxative effect, but no human trial has been published, and it will not supply iron.

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What the science says

  • Laxative action Limited evidence

    A comprehensive review of Rumex crispus documents anthraquinone constituents of the same class that make senna and rhubarb work, which supports a plausible stimulant laxative effect. No clinical trial of yellow dock as a laxative exists.

  • It does not treat iron deficiency Limited evidence

    The root contains very little iron and is high in oxalate, which binds iron rather than delivering it. The traditional association is with bitter digestive stimulation, not with correcting anaemia, which requires diagnosed treatment with iron salts.

  • Other activity is preclinical Limited evidence

    Laboratory studies report α-glucosidase inhibition and antihyperglycaemic activity of Rumex crispus extracts in animal models. This is early-stage work with no human follow-up.

Dosage & safety

Studied doseNo studied dose. Traditional use is 1–2 g of dried root as a decoction, or 1–2 mL of tincture, up to three times daily, and stimulant laxative herbs should not be used continuously for more than about a week.
SafetyHigh in oxalate: cases of severe and fatal oxalate poisoning have been reported after eating large quantities of Rumex leaves, and it is a poor choice for anyone with a history of calcium oxalate kidney stones or kidney disease. As an anthraquinone laxative it can cause cramping and, with chronic use, electrolyte loss. Avoid in pregnancy, breastfeeding and bowel obstruction.

How to take it

TimingTraditionally taken in the evening for a morning effect; do not use it continuously for more than about a week.
With food?Take with plenty of water; food reduces the cramping.
Worth knowingIf you have ever had a calcium oxalate kidney stone, skip this one entirely — Rumex species are among the highest-oxalate plants there are.

Interactions

With medications

  • digoxin

    Potassium loss from chronic stimulant-laxative use increases digoxin toxicity. do not use laxative herbs regularly if you take digoxin

  • diuretics and corticosteroids

    Additive potassium loss, which can cause weakness and arrhythmia. do not combine beyond occasional short-term use

  • any oral medication

    Faster gut transit reduces how much of an oral drug is absorbed. separate by at least 2 hours

With other supplements

  • iron and calcium supplements

    The oxalate and tannin content binds these minerals and reduces absorption. separate by at least 2 hours

  • other stimulant laxative herbs (senna, cascara, rhubarb root)

    Additive cramping and electrolyte loss. do not stack them

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does yellow dock help with iron deficiency?

No. Yellow dock root contains very little iron and is high in oxalate, which binds iron rather than delivering it; anaemia needs diagnosed treatment with iron salts.

Does yellow dock work as a laxative?

Plausibly, since yellow dock contains anthraquinones of the same class as senna, but no clinical trial of yellow dock as a laxative exists, so the evidence is limited. Do not use it continuously for more than about a week.

Is yellow dock safe if you have had kidney stones?

No. Rumex species like yellow dock are among the highest-oxalate plants, so skip it entirely if you have had calcium oxalate kidney stones or kidney disease. Avoid it in pregnancy, breastfeeding and bowel obstruction too.

Can you take yellow dock with digoxin or diuretics?

Not regularly: potassium loss from chronic stimulant-laxative use like yellow dock increases digoxin toxicity and adds to potassium loss from diuretics and corticosteroids. Separate yellow dock from other oral medications by at least 2 hours.

Scientific references

Related in General health

Herbal medicines: what the evidence says (335)