Yellow Dock - Drug Monograph

Introduction

Yellow Dock (Rumex crispus) is a perennial herb native to Europe and Western Asia that has been naturalized in North America. Traditionally used in herbal medicine, it belongs to the Polygonaceae family. While not an FDA-approved pharmaceutical drug, it is commonly used as an herbal supplement with historical applications in various traditional medicine systems including Western herbalism, Ayurveda, and Traditional Chinese Medicine.

Mechanism of Action

The pharmacological activity of Yellow Dock is attributed to several constituents:

• Anthraquinone glycosides (emodin, chrysophanol): Provide mild laxative effects through stimulation of colonic peristalsis and inhibition of water and electrolyte reabsorption in the large intestine
• Tannins: Provide astringent properties
• Iron compounds: May contribute to its traditional use for iron deficiency
• Antioxidant compounds: Demonstrate free radical scavenging activity in vitro

The laxative effect typically occurs 6-12 hours after administration, similar to other anthraquinone-containing herbs.

Indications

• Occasional constipation (short-term use)
• Traditional use for skin conditions (eczema, psoriasis)
• Traditional use as a "blood purifier" and for anemia
• Topical applications for skin irritations
• Digestive complaints (dyspepsia, liver support)

Dosage and Administration

• Dried root: 2-4 grams daily in divided doses
• Tincture (1:5): 2-4 mL three times daily
• Fluid extract (1:1): 1-2 mL three times daily
• Tea: 1 cup 2-3 times daily (steep 1-2 teaspoons dried root in 150mL boiling water for 10-15 minutes)

• Pregnancy/Lactation: Contraindicated
• Pediatrics: Not recommended due to lack of safety data
• Hepatic/renal impairment: Use with caution

Pharmacokinetics

Limited human pharmacokinetic data exists. Based on similar anthraquinone-containing plants:

• Absorption: Anthraquinone glycosides are poorly absorbed from the small intestine; converted to aglycones by colonic bacteria
• Distribution: Limited systemic distribution; primarily acts locally in colon
• Metabolism: Hepatic metabolism via glucuronidation and sulfation
• Elimination: Primarily excreted in feces; some renal elimination of metabolites

Contraindications

• Intestinal obstruction
• Appendicitis
• Crohn's disease
• Ulcerative colitis
• Abdominal pain of unknown origin
• Pregnancy and lactation
• Children under 12 years
• Severe dehydration or electrolyte imbalance
• Known hypersensitivity to Rumex species

Warnings and Precautions

• Prolonged use: May lead to electrolyte imbalance, hypokalemia, and dependence
• Cathartic colon: Chronic use may cause atonic colon with impaired function
• Discoloration: May cause reddish-pink discoloration of urine (harmless)
• Electrolyte monitoring: Recommended with extended use
• Surgery: Discontinue at least 2 weeks prior to elective surgery due to potential electrolyte effects

Drug Interactions

• Diuretics: Increased risk of hypokalemia
• Corticosteroids: Enhanced potassium-wasting effects
• Cardiac glycosides: Hypokalemia may potentiate digitalis toxicity
• Antiarrhythmic drugs: Electrolyte imbalance may affect drug efficacy
• Lithium: May alter lithium concentrations
• Anticoagulants: Theoretical interaction due to vitamin K content

Adverse Effects

• Abdominal cramping
• Diarrhea
• Nausea
• Urine discoloration (reddish-pink)

• Electrolyte imbalance (hypokalemia)
• Dehydration
• Protein-losing enteropathy (chronic use)
• Stevens-Johnson syndrome (rare)
• Hepatitis (case reports)

Monitoring Parameters

• Electrolytes (particularly potassium) with prolonged use
• Hydration status
• Bowel function patterns
• Signs of dependence or need for escalating doses
• Liver function tests with extended use

Patient Education

• Use only for short-term relief of occasional constipation
• Do not exceed recommended duration (7-10 days)
• Maintain adequate fluid intake
• Report any abdominal pain, cramping, or changes in bowel habits
• Be aware of urine discoloration (harmless)
• Inform healthcare providers of all supplement use
• Do not use during pregnancy or breastfeeding
• Seek medical attention if constipation persists beyond 1 week

References

1. World Health Organization. (1999). Monographs on Selected Medicinal Plants, Volume 1. 2. European Medicines Agency. (2018). Assessment report on Rumex crispus L., radix. 3. Brinker F. (2010). Herb Contraindications and Drug Interactions. 4th ed. 4. Wichtl M. (2004). Herbal Drugs and Phytopharmaceuticals. 5. Natural Medicines Comprehensive Database. (2023). Yellow Dock. 6. Bradley PR, ed. (1992). British Herbal Compendium, Volume 1. 7. Mills S, Bone K. (2005). The Essential Guide to Herbal Safety. 8. American Herbal Products Association. (2020). Botanical Safety Handbook.