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Western herbalism

Yellow dockRumex crispus

Yellow dock root is a traditional mild laxative and bitter; we could find no human trial of it, and its main compounds are laxative anthraquinones.

Botanical name
Rumex crispus
Part used
root
Also called
Curly dock, Curled dock
Used in
Western herbalism
Taken for
Constipation, Liver and bile
Sold as
decoction, capsules, powder, tincture, tea

What yellow dock is

Yellow dock is the root of Rumex crispus, a perennial of the knotweed family (Polygonaceae) that grows as a weed across much of the world. It has long leaves with curly edges and a thick taproot that is yellow inside, which gives the herb its common name. The medicinal material is the dried root, sold as cut root, powder, capsules, a decoction and an alcohol tincture, and it is one of the roots that turn up in digestive bitters and in some multi-herb cleanse formulas.

The genus Rumex has about 200 species, and several are eaten as vegetables or used as medicines. A close relative, Rumex japonicus, is a folk medicine in East Asia, where the root is called yang ti. The root of yellow dock contains anthraquinones such as emodin, the same chemical family that makes senna and cascara stimulant laxatives, together with naphthalene derivatives and flavonoids. Some dock species also carry a high level of oxalic acid.

What the traditions use it for

Western herbalism

Western herbal tradition classes yellow dock root as a mild laxative and astringent, a bile-stimulating herb and a “blood cleanser.” A review of the species lists astringent, laxative, diuretic, mild tonic, blood cleanser, spasmolytic (cramp-easing) and cholagogue (bile-stimulating) as the roles it has been given in different countries. A review of the whole genus adds constipation, diarrhea, jaundice and liver and gallbladder disorders among the conditions treated with dock species. These are the tradition’s ideas about the plant. They are not findings from clinical trials.

The constituents

About 224 constituents have been identified in Rumex crispus, including anthraquinones, naphthalene derivatives, flavonoids, essential oil, coumarins and stilbenes. The anthraquinones are the likely basis of the laxative use, since the Natural Medicines database says they work as stimulant laxatives. Laboratory work reports antitumor, antimicrobial, antioxidant and anti-inflammatory activity; emodin from the root helped explain activity against MRSA bacteria in a dish. A water extract of the leaf killed 83 percent of a model roundworm, C. elegans, in a dish. None of these findings has been tested in people.

The human evidence

We could find no randomized trial or controlled study in people of yellow dock root, by itself or in a named formula, for constipation, bile flow or any other gut outcome. The Natural Medicines database rates the evidence as insufficient to rate for constipation and for each of its other listed uses. The anthraquinone laxatives that do have trial records come from other plants, such as senna, and those trials do not transfer to yellow dock.

What exists is review and laboratory work. A review of Rumex crispus counts about 224 compounds and summarizes antitumor, antimicrobial, antioxidant, anti-inflammatory, anti-osteoporotic and antidiabetic activity in cells and animals. The same review reports that the plant is toxic and has adverse effects, including allergy and symptomatic thrombocytopenia (a drop in platelets with symptoms). A review of the genus lists constipation and diarrhea among traditional uses and warns that high oxalic acid levels in some species can cause kidney stones when large quantities are eaten. In a model-organism study, a water extract of yellow dock leaf produced 83 percent lethality in Caenorhabditis elegans over up to 72 hours, which is a lab result in a free-living roundworm and not a result in a human intestinal parasite.

What has not been tested in people: whether yellow dock root loosens stools at all, at what dose, how it compares with senna or with fiber, how much anthraquinone a given product contains, and what happens with regular use.

StudyDoseWhat it found
Review of Rumex crispus: botany, traditional use, chemistry, pharmacology and safety PMID 39520965Not applicableAbout 224 compounds; laxative, astringent and cholagogue traditional roles; laboratory antitumor, antimicrobial and anti-inflammatory activity; adverse effects include allergy and symptomatic thrombocytopenia
Review of the genus Rumex: traditional uses, chemistry and pharmacology PMID 26384001Not applicableConstipation and diarrhea among traditional uses; high oxalic acid in some species can cause kidney stones in large amounts; calls for studies of safety and efficacy before clinical trials
Laboratory study of Rumex crispus root and fractions against MRSA PMID 34695862In vitroEmodin and other constituents contributed to antimicrobial activity against MRSA in a dish; no human data
Model-organism study of Rumex crispus extracts against the roundworm C. elegans PMID 35002450In vitro, up to 72 hoursWater extract of leaf gave 83% lethality; not tested in humans or in human gut parasites
Natural Medicines database rating of yellow dock (via RxList)No dose range establishedInsufficient evidence to rate for constipation, respiratory inflammation, bacterial infections, jaundice and other uses

Doses, in trials and in practice

No human trial gives a dose, so there is no studied amount to quote. The Natural Medicines database states there is not enough scientific information to determine an appropriate range of doses for yellow dock. Traditional preparations are a decoction of the dried root, a root powder or capsule and an alcohol tincture. The same database says raw or uncooked yellow dock should not be used. Product labels differ in root amount and in extract type, so a label amount cannot be matched to an amount that has been studied.

The amounts above are what trials and pharmacopoeias record, not a dose for you; your medicines and conditions change the answer, and a clinician or pharmacist who knows them is the person to ask.

What is known about safety

The Natural Medicines database rates yellow dock as possibly safe for most adults in amounts found in food. It lists diarrhea, nausea, stomach cramps, excessive urination, skin irritation and low potassium and calcium from taking too much, and says handling the raw plant can irritate skin. Oral use in pregnancy and breastfeeding is rated likely unsafe because of the laxative effect and because the active chemicals pass into breast milk. It advises caution with clotting disorders, ragweed allergy, any blockage of the digestive tract, stomach or intestinal ulcers and a history of kidney stones. The review of Rumex crispus calls the plant toxic with allergic reactions and symptomatic thrombocytopenia reported, and the genus review attributes kidney-stone risk to its oxalic acid.

Where it meets prescription medicines

The Natural Medicines database rates two interactions major. Anthraquinone laxatives can lower potassium, and low potassium increases the side effects of digoxin, so that combination is flagged; the same potassium loss is flagged with diuretics (water pills). Yellow dock is also rated moderate with warfarin, because diarrhea from the root may increase warfarin’s effects and the chance of bleeding. These ratings are drawn from the laxative class and theory, not from interaction studies of yellow dock itself.

Catalog entries that list yellow dock

If you want yellow dock in a product rather than as a loose herb, these are the entries that carry it, with the label amounts and the reviews read.

Omyo GLP-1 Digestive Support 4.8 out of 5 from 2,814 ratings from omyohealth.com · $2.00 a day Urban Moonshine Original Digestive Bitters 4.4 out of 5 from 1,409 ratings from Amazon · $0.68 a day

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Herbs that sit beside it

Western / TCM Burdock Arctium lappa Western / TCM Dandelion Taraxacum officinale (and T. mongolicum in Chinese medicine) Ayurvedic / Western Senna Senna alexandrina (Cassia senna, Cassia angustifolia) Western Cascara sagrada Rhamnus purshiana (Frangula purshiana) TCM / Western Rhubarb root Rheum palmatum; Rheum officinale

Questions people ask

Does yellow dock work as a laxative?

Yellow dock root contains anthraquinones, a chemical family that includes the stimulant laxatives in senna and cascara, and tradition uses it as a mild laxative. We could find no human trial of the root, and the Natural Medicines database rates the evidence for constipation as insufficient.

Is yellow dock the same as other docks?

No. The genus has about 200 species, and they differ in chemistry; some carry a high level of oxalic acid. A related species, Rumex japonicus, is a separate East Asian folk medicine called yang ti.

Why is yellow dock flagged with digoxin and water pills?

Anthraquinone laxatives can lower potassium, and low potassium raises the risk of digoxin side effects and adds to the potassium loss from water pills. The Natural Medicines database rates both combinations major.

Is yellow dock safe during pregnancy?

The Natural Medicines database rates oral use as likely unsafe in pregnancy and breastfeeding. It cites the laxative effect and the passage of the active chemicals into breast milk.

Can raw yellow dock be eaten?

The Natural Medicines database says not to use raw or uncooked yellow dock. A review of the genus notes that high oxalic acid in some dock species can cause kidney stones when large quantities are eaten.

Sources