Related Terms

• Curled dock, curley dock, curly dock, Polygonaceae (family), Rumex crispus, Rumex obtusifolius, yellow dock root.

Background

• Yellow dock is often described as helping strengthen the blood; however, very few laboratory or human studies have been conducted to confirm this traditional use.

• Yellow dock is one of the original plants in the Native American anticancer herbal formula now known as Essiac®. In some versions of Essiac® yellow dock is substituted for the sheep's sorrel.

• The roots have been taken internally to build healthy blood, protect the liver, or act as an antifungal or laxative. As a seed tea, yellow dock may heal mouth sores and help diarrhea. Externally, yellow dock has been used to dissolve lumps and as an antitumor and antifungal. Yellow dock root (herb and salad green) is an astringent that has been banned in Canada.

Scientific Evidence

Tradition/Theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.

• Acne, anemia, antifungal, anorexia, arthritis, choleretic (bile flow stimulant), blood purifier (tonic), cancer, candidal infection (rash), chronic fatigue syndrome, common cold, constipation, cramps, detoxification, diarrhea, energy booster, exhaustion, hepatitis, high cholesterol, inflammatory skin disorders (eczema, psoriasis), laxative, lymphatic disorders, menopause, mouth sores, oral hygiene, premenstrual syndrome (PMS), skin conditions (dark circles under the eyes), tonic (liver).

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)

• There is no proven safe or effective dose for yellow dock in adults. Herbalists have recommended the roots and seeds daily for up to 12 months. As a tincture of the fresh roots, 10-60 drops has been used (20 drops, two or three times a day). A fresh root vinegar preparation (1-2 tablespoons or 30 milligrams) has also been used. Based on expert opinion, no more than one cup (250 milligrams) of the dried seed tea should be taken per day.

Children (younger than 18 years)

• There is no proven safe or effective dose for yellow dock in children.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

• Avoid in individuals with a known allergy or hypersensitivity to yellow dock or its constituents. Individuals allergic to ragweed pollen may also be allergic to yellow dock pollen.

Side Effects and Warnings

• There are very few available reports on the safety of yellow dock. A report exists of a fatal poisoning, with liver and kidney poisoning, after the consumption of large quantities of the leaves (several hundred grams). Use cautiously in patients with compromised renal (kidney) or hepatic (liver) function.

• Yellow dock contains anthraquinones, which act as laxatives. Anthraquinone laxative abuse may be associated with colon cancer.

Pregnancy and Breastfeeding

• Yellow dock is not recommended in pregnant or breastfeeding women due to a lack of available scientific evidence. Based on expert opinion, pregnant women should not ingest harsh laxatives. Yellow dock is thought to fall into this category, perhaps due to the anthraquinone content. However, other herbal experts have recommended yellow dock in pregnancy because of its iron content, although this has not been proven in clinical trials.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

• Yellow dock may have estrogenic activity, although more research is needed to clarify the exact mechanism of action. Caution is advised when taking drugs with estogenic activity due to possible additive effects.

• A fatal poisoning from yellow dock (Rumex crispus) occurred after ingestion of a large quantity of the fresh leaves as a salad vegetable. Pathological findings included liver and kidney damage, which may have been caused by the tannins found in the leaves. Caution is advised in patients with liver or kidney problems, or in patients who are taking drugs that affect the liver or kidneys.

• Yellow dock contains anthraquinones. In theory, yellow dock may have additive effects with other laxative agents.

• Yellow dock contains tannins and may increase the risk of side effects when taken with other agents that contain tannins.

Interactions with Herbs and Dietary Supplements

• A fatal poisoning from yellow dock (Rumex crispus) occurred after ingestion of a large quantity of the fresh leaves as a salad vegetable. Pathological findings included liver and kidney damage, which may have been caused by the tannins found in the leaves. Caution is advised in patients with liver or kidney problems, or in patients who are taking herbs or supplements that affect the liver or kidneys.

• Yellow dock contains anthraquinones. In theory, yellow dock may have additive effects with other laxative agents.

• Yellow dock may have estrogenic activity, although more research is needed to clarify the exact mechanism of action. Caution is advised when taking herbs or supplements with estogenic activity due to possible additive effects.

• Yellow dock contains tannins and may increase the risk of side effects when taken with other herbs or supplements that contain tannins.

Author Information

• This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

1. Reig R, Sanz P, Blanche C, et al. Fatal poisoning by Rumex crispus (curled dock): pathological findings and application of scanning electron microscopy. Vet Hum Toxicol 1990;32(5):468-470. View Abstract

2. Shen HD, Chang LY, Gong YJ, et al. [A monoclonal antibody against ragweed pollen cross-reacting with yellow dock pollen]. Zhonghua Min Guo.Wei Sheng Wu Ji.Mian.Yi.Xue.Za Zhi. 1985;18(4):232-239. View Abstract