Yellow dock ( Rumex crispus) is a perennial flowering herb, native to Europe, which grows throughout the United States. Its yellow roots were traditionally thought to have medicinal properties, and its sour-sweet leaves can be used (in moderation) as a salad green.
Historically, the plant has been used to treat a variety of problems, including constipation and diarrhea, as well as dermatitis and venereal diseases.1 Powdered yellow dock root has also been used as a mouthwash or dentifrice.
Yellow dock root has no established medical uses. However, it contains chemicals called anthroquinones (also found in the more famous herbal laxative senna),2 which stimulate bowel movements. For this reason, yellow dock is occasionally included in herbal laxative mixtures.
Like many other plants, yellow dock contains a substantial amount of tannins. These have astringent properties that may offer some benefit for treating minor skin wounds and hemorrhoids. Yellow dock is also sometimes recommended for nasal and lung congestion.
Typical doses of yellow dock root are 2 to 4 g of the dried root, 2 to 4 ml of the liquid extract, or 1 to 2 ml of the tincture.3
Comprehensive safety studies of yellow dock have not been performed, and for this reason it should not be used by pregnant or nursing women, young children, or individuals with severe liver or kidney disease.
As with any stimulant laxative, yellow dock should not be used if there is an intestinal obstruction. Possible side effects of overuse include cramps, diarrhea, nausea, intestinal dependence on the laxative, and excessive loss of potassium.4
In addition, yellow dock (like spinach) contains oxalic acid. Consuming excessive quantities of oxalic acid can cause severe toxic symptoms including vomiting and abdominal pain, and, in extreme cases, kidney stones or kidney failure. One case of fatal yellow dock poisoning has been documented.5 The victim, who had diabetes, ingested one kilogram of the raw herb in a salad, and died of liver and kidney failure. The liver failure was not explained.
1. McGuffin M, ed. American Herbal Products Association’s Botanical Safety Handbook. Boca Raton, FL: CRC Press; 1997:100, 148–9, 155–7.
2. Newall CA, Anderson LA, Phillipson JD . Herbal Medicines: A Guide for Health-Care Professionals . London, UK: Pharmaceutical Press; 1996:274.
3. Newall CA, Anderson LA, Phillipson JD . Herbal Medicines: A Guide for Health-Care Professionals . London, UK: Pharmaceutical Press; 1996:274.
4. Newall CA, Anderson LA, Phillipson JD . Herbal Medicines: A Guide for Health-Care Professionals . London, UK: Pharmaceutical Press; 1996:274.
5. 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;32:468–470.
Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 12/15/2015