A perennial herb that grows to 3 to 4 feet, yellow dock has narrow, slender light green leaves with undulated margins. It flowers in June and July. ² Although native to Europe, it grows throughout the United States. The yellow roots (deep, spindle-shaped) and rhizomes are used medicinally.

The spring leaf stalks of this plant have been used as a potherb in salads but is disagreeable to some because of its tart sour-sweet taste. The plant must be boiled and rinsed thoroughly before being eaten. Due to its astringent properties, the plant has been used generally unsuccessfully in the treatment of venereal diseases and skin conditions. The powdered root has been used as a natural dentifrice. Larger amounts have been given as a laxative and tonic.

The plant contains oxalate, most probably in the form of potassium oxalate crystals. ^3,  Anthraquinones (emodin, chrysophanic acid, physcion) have been identified, and the total anthraquinone content of the root (approximately 2%) exceeds that of medicinal rhubarb (Rheum rhaponticum, 1.4%), also a member of the family Polygonaceae. ⁴

Little is known about the pharmacology of yellow dock. The anthraquinone content most likely contributes to the laxative effect of the plant. The tannin component, however, may cause constipation. The related plant R. hymenosepalus (dock) contains a tannin that, upon hydrolysis, yields leucodelphinidin and leucopelargonidin, 2 compounds with potential antineoplastic activity. ⁵

There is no recent clinical evidence to support specific dose recommendations for yellow dock. Caution is warranted due to oxalate content.

Documented adverse effects; contains anthraquinones. Avoid use. ¹

None well documented.

The oxalate crystals damage mucosal tissue resulting in severe irritation and possible tissue damage. The ingestion of large amounts of oxalates may result in gastrointestinal symptoms; systemic absorption of oxalates may result in kidney damage. Ingestion of the plant by livestock has resulted in death. The stewed leaf stalks can be eaten as a potherb, but mature and uncooked leaves should be avoided. One traditional remedy for dermatitis and rashes suggest applying the juice of Rumex spp. However, sensitive people may develop dermatitis after contact with yellow dock.

Overdoses of the root extract may cause diarrhea, nausea, and polyuria in humans.