Yellow dock—also called curly dock and sour dock—is a member of the buckwheat family that can be found naturalized in many parts of the world. Originally from northern Europe and Asia, it has a long history of use in traditional medicines as a digestive aid, for skin conditions, and for liver health. Yellow dock is known as an astringent due to its content of tannins, which may be the reason for its use in skin conditions. Yellow dock extracts have been confirmed to have antioxidant and antimicrobial activity. Additionally, yellow dock contains the anthraquinone glycosides, a group of compounds that are known for their laxative activity. The antraquinone glycosides are also the primary active components in other popular herbal laxatives, such as senna, cascara and aloe. The bitter principles of yellow dock leaves make them useful as digestive aids. Yellow dock is also rich in iron (Bruneton, 1995).
Yellow dock lacks clinical backing as a single phytotherapeutic agent, however, the anthraquinone glycosides are well known and have clinically confirmed activity.
No clinical studies could be found that used yellow dock alone as a therapeutic agent, however, several clinical studies confirm the activity of the anthraquinone glycosides from other herbal laxatives.
Safety / Dosage
The laxative effect of yellow dock appears to be mild and safe. The fresh leaves are high in oxalates, and there have been a few reports of yellow dock toxicity in grazing sheep and at least one report of a human toxicity. If the oxalates are taken in high amounts they may inhibit nutrient absorption. Root preparations are typical, and the dosage is generally 1 gram of the dried root daily or 3-4 ml of the root extract, 3 times daily.
As with any laxative product, caution should be used by anyone who is pregnant or nursing.
1.Bruneton, J. Pharmacognosy, Phytochemistry, Medicinal Plants. 1995. Lavoisier Publishing, New York.
2.Gunaydin K, Topcu G, Ion RM. 1,5-dihydroxyanthraquinones and an anthrone from roots of Rumex crispus. Nat Prod Lett. 2002 Feb;16(1):65-70
3.Panciera RJ, Martin T, Burrows GE, Taylor DS, Rice LE. Acute oxalate poisoning attributable to ingestion of curly dock (Rumex crispus) in sheep. J Am Vet Med Assoc. 1990 Jun 15;196(12):1981-4.
4.Reig R, Sanz P, Blanche C, Fontarnau R, Dominguez A, Corbella J. Fatal poisoning by Rumex crispus (curled dock): pathological findings and application of scanning electron microscopy. Vet Hum Toxicol. 1990 Oct;32(5):468-70.
5.Yildirim A, Mavi A, Kara AA. Determination of antioxidant and antimicrobial activities of Rumex crispus L. extracts. J Agric Food Chem. 2001 Aug;49(8):4083-9
EDITOR'S NOTE: This monograph can be found in The Health Professional's Guide to Dietary Supplements (Lippincott, Williams & Wilkins) by Shawn M. Talbott, PhD and Kerry Hughes, MS.