Yellow dock (Rumex crispus ) is a small, leafy plant that grows wild throughout the world. It belongs to the buckwheat or Polygonaceae family. It has yellowish-brown roots, which accounts for its common name. The roots are 8-12 in (20-30 cm) long, about 0.5 in (1.27 cm) thick, fleshy, and usually not forked. The stem is 1-3 ft (0.3-0.9 m) high and branched. Yellow dock is also known as curly or curled dock because of its long lance shaped leaves that are slightly ruffled along its edges. The leaves are 6-10 in (15-25 cm) long. Its leaves are used for food while both roots and leaves are used as herbal remedies. Yellow dock is closely related to rhubarb and sorrel.
In terms of chemical analysis, yellow dock contains anthraquinone glycosides, tannins, rumicin, and oxalates, including potassium oxalate.
Yellow dock is primarily used in the treatment of digestive problems, liver diseases, and skin disorders. It has been described as an alterative, astringent, cholagogue, hepatic, laxative, and nutritive.
Yellow dock contains relatively small amounts of anthraquinone glycosides, which are strong laxatives in larger doses. Since yellow dock contains only small amounts of these chemicals, however, it is used as a mild laxative. Yellow dock is also used to help support and restore liver function, which is why it is called a hepatic.
Applied externally as an antiseptic and an astringent, yellow dock has been used to treat skin cuts, swelling, rashes, boils, burns , bleeding hemorrhoids , dog and insect bites, and wounds . An ancient British charm that was chanted when dock is applied to skin irritations caused by stinging nettle illustrates the use of yellow dock as a skin treatment: "Nettle out, dock in, dock remove the nettle sting."
Yellow dock is also taken internally as a treatment for such skin conditions as psoriasis, eczema, acne , poison ivy, and other rashes, often in combination with such other herbs as red clover (Trifolium pratense ), dandelion root (Taraxacum officinalis ), cleavers (Galium aparine ), and burdock (Arctium lappa ).
Yellow dock also has been used in the treatment of liver and gallbladder disorders. It is called a cholagogue because it is thought to stimulate the production of bile and digestive fluids.
Yellow dock is nutritious, as it contains vitamin C, iron, calcium , and phosphorus . It even contains enough tannin to use in tanning leather.
Other uses of yellow dock by traditional herbalists have included the treatment of:
- swollen glands
Both the roots and leaves of yellow dock are used in remedies. Due to the mild and general nature of its actions, yellow dock is rarely used alone, but in combination with other herbal remedies. The roots are dug in late summer and autumn between the months of August and October. They are cleaned well and split lengthwise before drying. The roots are ground or crushed and then are used in preparing ointments, tinctures, decoctions, or teas. The ground root is kept cool and dry but not frozen.
Tea is prepared by boiling 1-2 tsp (5-10 g) of yellow dock root in 500 mL (2 cups) water for 10 minutes. Syrup is made by boiling 0.5 lb of crushed root in a pint of syrup. Dried extracts of yellow dock are also prepared as pills or capsules, and are available commercially. These commercial preparations are often a mixture of several different types of herbs. The directions on the label of the commercial product should be followed for recommended dosages.
For external applications, both roots and leaves are used. The root may be pounded and applied as a poultice. Fresh or boiled leaves and stems are directly placed on skin irritations. An ointment is made by boiling the root in vinegar until the fiber is softened. The pulp is then mixed with a solid grease such as petroleum jelly, animal fat, or vegetable shortening.
The young leaves of yellow dock may be eaten cooked as greens, but should not be eaten raw. If the plant is too bitter, it may be parboiled, washed, added to clear water, and cooked until tender. Since the leaves contain oxalic acid (similar to spinach), they should not be eaten frequently in large amounts as the oxalic acid can prevent the absorption of calcium. The seeds of yellow dock have been ground and used as flour.
Since no safe dosage has been established, pregnant or breastfeeding women and infants and children under the age of six should avoid the use of yellow dock. Persons with any chronic diseases of the gastrointestinal tract, such as duodenal ulcers, esophageal reflux, spastic colitis, diverticulosis, or diverticulitis , should not take yellow dock.
A person with a history of kidney stones should not use yellow dock, since the oxalates and tannins present in yellow dock may aggravate that condition.
When used as a laxative, yellow dock should not be used for more than a week, unless a doctor has ordered otherwise. Overuse of a laxative may lead to dependence. Any sudden changes in bowel habits or function that last longer than two weeks should be checked by a doctor before using a laxative. Children up to six years of age should not take a laxative unless prescribed by a doctor.
The side effects, especially if larger doses of yellow dock are taken, include diarrhea , skin eruptions, nausea , and vomiting . Kidney damage, characterized by blood in urine, decreased urine flow, and swelling of hands and feet may also occur.
To enhance the activity of yellow dock, it should be used in combination with such other herbs as red clover (Trifolium pratense ), dandelion root (Taraxacum officinalis ), cleavers (Galium aparine ), and burdock (Arctium lappa ).
Heatherly, Ana Nez. Healing Plants: A Medicinal Guide to Native North American Plants and Herbs. New York: The Lyons Press, 1998.